# eSATA RAID boxes



## Diacritical (Jan 10, 2003)

I am starting to put aside some duckets for an eRAID box for that great day when they allow expanded capacity (the S3 is full.. no room for suggestions). 

Does anyone have any sense whether RAID5 will work for this? We tend to avoid RAID5 in my business because of write bottlenecks and go with RAID1+0 -- but I don't want to waste that much capacity if I do not have to. I'm looking at a 2.5TB RAID5 array that might do the trick. if RAID5 is a problem with SATA drives, might I get past that by going to a SAS array with an eSATA connection? I don't want to spend more than $2-3k on this, but I will if it will make a difference. Noise is not a problem since it will go in an acoustical enclosure with it's own cooling unit, next to my home PC's SAS RAID arrays.


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## NetJunkie (Feb 19, 2003)

RAID5 w/ SATA will be just fine. Remember, it's using a single SATA right now. Yes, you'll lose some write performance with RAID5 but with 3 drives you'll be fine with the increased spindles.


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## rockhome (Dec 21, 2005)

Unless you are going to invest in some serious hardware, RAID 5 is all but useless. Typically, in large storage applications, the hardware is tailored with large, on disk caches and other tuning to make RAID 5 useful.

If you are buying an off the shelf product from a consumer electronics store, I'd recommend RAID 0 at the most, that is really all you need. A lot of the decisions sort of depend on how the eSATA port on the S3 will be managed. RAID 5 is wholly unnecessary and could cause some problems if you lose a drive.


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## jlib (Nov 22, 2002)

rockhome said:


> ...RAID 5 is wholly unnecessary and could cause some problems if you lose a drive.


As opposed to losing a drive in a RAID 0 config? 

I think the only reason to consider RAID 5 is to _avoid_ problems with losing a drive. Someone considering a multi-Terabyte RAID is probably interested in not losing 6 months of saved movies and shows and all of their Season Passes. You are probably right about the performance limitations but Tivo is an unchallenging application and any write bottlnecks would not likely be approached even with two simultaneous write streams and one read.


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## rodalpho (Sep 12, 2006)

RAID5 is the way to go. Tivo doesn't _need_ great write performance, and you can't beat the savings over RAID1 and 1+0.

RAID0 is foolish.


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## AbMagFab (Feb 5, 2001)

My main server is a ~2TB RAID5 array in my PC with all SATA 3GB drives. Not eSATA, but per your original question, no issues with RAID5 and SATA.

And you can use write-through or write-back, the latter for much improved write performance (at the expense of data loss if you're really unlucky with a hard outage at the wrong time).

My only mistake was not using a large enough power supply. Seagate's have the best warrantee, but don't support staggered start up, so it's a big hit on power when they all spin up at the same time (for 8 x 320GB, it's about 270W of power on a full start). Just some advice from experience - get the biggest power supply you can get (I have a 650W in my PC that's has the RAID5 array in it).


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## Diacritical (Jan 10, 2003)

Thanks, folks. I am willing to try a cheaper RAID5 solution first -- if it fails I can always use it somewhere else and replace it with a more robust RAID1+0 unit. 

RAID0 is not a serious option and RAID1 does not offer enough capacity to be worth the effort -- but RAID5 (very economical, fast reads, slow writes) may well work fine. When you consider the actual transfer rates (6MB/hour/stream???), all you should need is fast seek times for it to work well... 

Now for the interesting part -- getting eSATA enabled and figuring out just how large a volume the TiVo will support.


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## Jazhuis (Aug 30, 2006)

I do have one theoretical question; do any of the raid enclosures you're looking at do auto-repair and rebuild? While I'm sure there are some (for the $$$), I'm thinking that there certainly won't be any software interface through the S3 to initialize a drive replacement and subsequent rebuild.

_Edit:_ Yeah, while I can find drive arrays that have, for instance, an ethernet port for web-based configuration, I think most people will be far below the $10k rack-mount storage device range. Anyone have some sort of insight?


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## JamieP (Aug 3, 2004)

Keep in mind that the MFS file system can't be larger than 2TiB (512 byte block size with 32 bit unsigned integers for block addresses = 2^41 = 2TiB).

There are already some display problems when you go above 1TiB, presumably due to a few places in the code where signed integers are being used for size-in-blocks calculations. More details in this thread.


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## rodalpho (Sep 12, 2006)

Yeah, all of the enclosures with hardware RAID will do that, configured via serial port or web browser. The cheaper ones actually have multiple sockets to connect to your computer for software RAID, they won't work with the Tivo. Or at least not in RAID. Hardware RAID eSATA enclosures aren't consumer-level items right now; they're only used in linear editing and such. Expect to pay over $800 for the enclosure alone.


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## 1283 (Sep 8, 2000)

rodalpho said:


> Expect to pay over $800 for the enclosure alone.


$150. Someone bought it and will try it with S3 in the next few days.
http://www.newegg.com/Product/Product.asp?Item=N82E16822102002


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## rodalpho (Sep 12, 2006)

That's only two disks. RAID5 requires at least 3. It supports raid1 or raid0. Good for data protection, I guess, although you still have a non-mirrored disk inside the tivo.


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## Diacritical (Jan 10, 2003)

Jazhuis said:


> I do have one theoretical question; do any of the raid enclosures you're looking at do auto-repair and rebuild? While I'm sure there are some (for the $$$), I'm thinking that there certainly won't be any software interface through the S3 to initialize a drive replacement and subsequent rebuild.


I would only procure hardware RAID that does not require any support (aside from the eSATA interface) from the TiVo at all. All good hardware RAID enclosures will automatically rebuild (and I will have a hot-spare installed as well). In fact, connecting such a box is not impossible with TiVo as she is -- but I don't want to open the box and I'd much rather use the port once it is enabled.

This is not cheap, but it is worth the effort.

--


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## jlib (Nov 22, 2002)

JamieP said:


> Keep in mind that the MFS file system can't be larger than 2TiB (512 byte block size with 32 bit unsigned integers for block addresses = 2^41 = 2TiB)...


JamieP, thanks so very much for that heads up. I too have been contemplating rigging up a hardware RAID (in my case in lieu of the the internal drive). That bit of information will keep me on track in not going so overboard on capacity that I cause other problems.

Rodolpho, just in the last few months the market has been flooded with cheap Taiwanese hardware-based consumer RAID 5 enclosures (using single path SATA or eSATA host interfaces). There usually is little if any technical support for these products so buyer really needs to examine the website of the manufacturer to make sure they provide at least firmware updates (the chip is the thing with these units).

Here is the thread that c3 mentioned. It got a bit off the original subject but is now about the whole RAID thing (substituting for the internal drive in particular). Interested readers may be able to cull some information out of it but this is a more appropriately named one.


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## rodalpho (Sep 12, 2006)

Can you link to any? I'd love to setup an array with four cheap staples-special 250GB drives for the tivo.


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## greg_burns (May 22, 2004)

rodalpho said:


> Can you link to any? I'd love to setup an array with four cheap staples-special 250GB drives for the tivo.


http://www.cooldrives.com/sata-raid1.html

Specifically...
http://www.cooldrives.com/harasaiipomu.html



> Easy Plug and Play Setup on any Port Multiplier Compatible Host adapter.


Does this mean this wouldn't work with an S3? Does the S3's eSata port of have this circuitry?


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## jlib (Nov 22, 2002)

RAID 5; $290.05. This looks the same as the Accusys unit so they are probably the OEM. A user would want to go with an external power supply I think rather than tapping into the S3 power with 3 drives. For about $1K you have a fault-tolerant 1 TiB of storage (assuming 3 of the super quiet WD Caviar 500GB drives).


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## 1283 (Sep 8, 2000)

greg_burns said:


> http://www.cooldrives.com/sata-raid1.html
> 
> Specifically...
> http://www.cooldrives.com/harasaiipomu.html
> ...


RAID 0 and SPAN (concatenation) modes would work with TiVo, but you have to set up the box through a PC. It is very unlikely that TiVo's SATA hardware is port multiplier aware, but you do not need that functionality when the box is configured as a single virtual drive.


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## jlib (Nov 22, 2002)

For our application the following terms in the description on a RAID enclosure equal incompatibility (i.e., they require controller cards or software drivers): Port Multiplier, Multilane, Infiniband and any with individual cables to the hard drives instead of one to the enclosure.


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## 1283 (Sep 8, 2000)

Some boxes can provide more features with a port multiplier host and/or host software, but they can also be run standalone (compatible with TiVo) with less functionality.


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## rodalpho (Sep 12, 2006)

$300 is still a bit more than I'm looking to pay, and I can't find any reviews of those units anywhere. But anyway, thanks for the links, hopefully prices will drop shortly.


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## HDTiVo (Nov 27, 2002)

A year and change has passed and the TiVo HD is out. THD is perfect for this because you can use its eSATA port.

What are people using for inexpensive RAID5 solutions that would work with the THD?

I tried a Buffalo DriveStation Quattro but could not get it to work. I suspect it was related to it being a SATA I interface (or the internal drives are actually PATAs)


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## TexasGrillChef (Sep 15, 2006)

I don't know if anyone has mentioned this yet.

Since I didn't read through all 21 posts so far.

But Are you aware... that the S3 is only capable of having 2 Terabytes worth of HD space.
Thats INTERNAL AND EXTERNAL combined.

So even if you do plug in a 4TB RAID server (BTW Try X-RAID, even better then Raid 5, thats X-raid.. NOT Raid 10) It WON"T see all of your drive space.

The S3 is limited to total of 2 Terbytes for both internal AND external drives combined.

TGC


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## mattack (Apr 9, 2001)

JamieP said:


> Keep in mind that the MFS file system can't be larger than 2TiB (512 byte block size with 32 bit unsigned integers for block addresses = 2^41 = 2TiB).


I realize this is an old post, but this is no longer true on the TivoHD is it? I thought they changed the FS somehow (going to 64 bit ints?)


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## TexasGrillChef (Sep 15, 2006)

mattack said:


> I realize this is an old post, but this is no longer true on the TivoHD is it? I thought they changed the FS somehow (going to 64 bit ints?)


I don't know what they changed on the HD unit. But I do know the max on the HD unit is larger than the S3. The HD unit has a max of 3TB.

TGC


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## jlib (Nov 22, 2002)

In the context of the original date of this thread, RAID made sense since the largest quiet single drive you could get was only 500GB. Also, statements about size limitations have to be taken in the context of the time. Spike2k5 has demonstrated a 312 Hour 2.5TB TiVo HD.


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## SCSIRAID (Feb 2, 2003)

TexasGrillChef said:


> I don't know if anyone has mentioned this yet.
> 
> Since I didn't read through all 21 posts so far.
> 
> ...


I think you will find that x-raid in its 3 and 4 drive examples IS RAID 5. It essentially allows for automatic migration between a single drive (1x capacity) to a 2 drive RAID 1 (1x capacity) and then to a 3 drive RAID 5 (2x capacity) and then a 4 drive RAID 5 (3x capacity) where x is the capacity of a single drive.


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## HDTiVo (Nov 27, 2002)

I brought this back up for the *THD* because you can take advantage of both the_ larger disk size limit _ and the eSATA port for a single drive.

The advantages are: RAID gives you data protection; and using an external gives you easy access for future upgrades and backup, as well as the ability to use _multiple enclosures or sets of drives _ for even more storage.

I imagine product choices have changed somewhat in variety and price since 13 months ago.


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## Thom (Jun 5, 2000)

HDTiVo -

Your private message space is full; no one can send you any PMs.

Did you get your TiVo to boot from your RAID?


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## TexasGrillChef (Sep 15, 2006)

SCSIRAID said:


> I think you will find that x-raid in its 3 and 4 drive examples IS RAID 5. It essentially allows for automatic migration between a single drive (1x capacity) to a 2 drive RAID 1 (1x capacity) and then to a 3 drive RAID 5 (2x capacity) and then a 4 drive RAID 5 (3x capacity) where x is the capacity of a single drive.


Yes 4 Drive X-Raid is basiclly Raid 5, yet it has the capability of being able to upgrade the drives to larger hard drives on the fly. Without wiping out data, or the raid partition. Which is nice.

TGC


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## HDTiVo (Nov 27, 2002)

TexasGrillChef said:


> Yes 4 Drive X-Raid is basiclly Raid 5, yet it has the capability of being able to upgrade the drives to larger hard drives on the fly. Without wiping out data, or the raid partition. Which is nice.
> 
> TGC


That is much nicer than the Drivestation Quattro.

How do I find this product?

Thanks.


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## jlib (Nov 22, 2002)

HDTiVo said:


> ...How do I find this product?


It is more of a technique than a particular product. Netgear's Enfrant patented the method. I don't know if it has been licensed to anyone else. Since they only make network attached storage solutions it is not likely you are going to find anything applicable.


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## HDTiVo (Nov 27, 2002)

So far no one has posted anything current that fits the bill. Maybe there is a reason I can't find a solution. :frown:


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## flatcurve (Sep 27, 2007)

I thought the THD's limit was closer to 8GB? maybe I misread a 3 as an 8.

Anyway... if redundant storage is your biggest concern, you need to find a way to eliminate the internal drive of the tivo from the equation. One of the cool things about the THD is that you can just swap the SATA cables on the motherboard. That way you'd be running the unit entirely from the external RAID and never have to worry about data loss again. Otherwise, what's the point in spending all that money on the RAID when your internal drive fails?

I haven't tried this method myself, for lack of a decent RAID setup.


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## HDTiVo (Nov 27, 2002)

Thom said:


> HDTiVo -
> 
> Did you get your TiVo to boot from your RAID?


No, I tried quite a bit though. Maybe if they come out with a new model that is SATA II.

Buffalo is now doing duty on the PC.

I've also managed to get my prior Mirrors (Netgear SC101) to stop running. The mirrors keep breaking, so its useless for now. I didn't see anything on netgear's site that helped find the problem and haven't had time to call.



flatcurve said:


> Anyway... if redundant storage is your biggest concern, you need to find a way to eliminate the internal drive of the tivo from the equation. One of the cool things about the THD is that you can just swap the SATA cables on the motherboard. That way you'd be running the unit entirely from the external RAID and never have to worry about data loss again. Otherwise, what's the point in spending all that money on the RAID when your internal drive fails?


Exactly.


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## 1283 (Sep 8, 2000)

HDTiVo said:


> Maybe if they come out with a new model that is SATA II.


That's very unlikely to be the cause of the problem.


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## scoombs (Jun 23, 2002)

HDTiVo said:


> So far no one has posted anything current that fits the bill. Maybe there is a reason I can't find a solution. :frown:


This is what I currently have on-hand, but have not plunged for the S3/THD to test on yet. 

http://www.sansdigital.com/mobileraid/mr5ct2.html


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## 1283 (Sep 8, 2000)

scoombs said:


> This is what I currently have on-hand, but have not plunged for the S3/THD to test on yet.
> 
> http://www.sansdigital.com/mobileraid/mr5ct2.html


"max. 2TB per volume". TiVo can use only one volume.


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## scoombs (Jun 23, 2002)

c3 said:


> "max. 2TB per volume". TiVo can use only one volume.


Spike had demonstrated a 2.5TB THD some time ago, and felt that it could go much larger, he just did not have the drives available to test it.

http://www.mfslive.org/tivo_hd.htm


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## 1283 (Sep 8, 2000)

scoombs said:


> Spike had demonstrated a 2.5TB THD some time ago, and felt that it could go much larger, he just did not have the drives available to test it.
> 
> http://www.mfslive.org/tivo_hd.htm


The Sans Digital box can support maximum of 2TB per volume, so that's the limitation, not the THD.


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## scoombs (Jun 23, 2002)

c3 said:


> The Sans Digital box can support maximum of 2TB per volume, so that's the limitation, not the THD.


Gah...foiled before I even get started, unless 64-bit MFS will come to the rescue:

"* The 2TB limitation is caused by the Operating System. The driver for USB, Firewire and SATA in Windows XP 32 bit version does not support a volume greater than 2TB. In Windows Server 2003 64bit version, the SATA driver already supports more than 2TB per volume; once you convert it to GPT disk, the OS should recognize the whole capacity of the volume set. However, the driver for USB/Firewire in 64bit WIndows still does not support 2TB per volume. So, in order to fully utilize the volume which is greater than 2TB, you have to have 64bit Windows and connect your unit using the SATA interface."


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## 1283 (Sep 8, 2000)

Oh, I didn't know that 2TB limitation comes from Windows. If you can configure the box to have more than 2TB in a single volume, then TiVo should be able to use it.


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## HDTiVo (Nov 27, 2002)

c3 said:


> "max. 2TB per volume". TiVo can use only one volume.


TiVo could use 2 enclosures of 2TB each then. But that isn't what I am looking for for now.

You guys are talking about Windows drivers supporting... but I wonder if loaded with big drives the thing could be formatted/prepped by WinMFS at a larger size anyway and then used that way on the TiVo.

BTW, Buffalo apparently supports at least 4TB, because I asked tech support about that. Not that that does me any good vis a vis TiVo.


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## scoombs (Jun 23, 2002)

HDTiVo said:


> You guys are talking about Windows drivers supporting... but I wonder if loaded with big drives the thing could be formatted/prepped by WinMFS at a larger size anyway and then used that way on the TiVo.


Spike has demonstrated a 2.5TB THD, so we know the 64bit MFS limit is above that...what has not been confirmed is the upper limit. Once I clarify my options from the Service Holiday Special thread regarding getting service for my current S1, or buying a S2-DT with either the included service special or using the Fall rebate (thanks for the Amazon link HDTiVo) to get a qualifying unit to get the Lifetime option with a THD purchase, I will test it.

I plan to use a 5-drive 4TB RAID 5. Assuming the enclosure works, this will either confirm the upper limit (if it is below 4TB), or it will leave it unconfirmed for the time being.


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## HDTiVo (Nov 27, 2002)

scoombs said:


> Spike has demonstrated a 2.5TB THD, so we know the 64bit MFS limit is above that...


What did Spike use to create that 2.5TB drive?


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## scoombs (Jun 23, 2002)

His screenshots on mfslive.org just says:

"Tivo HD Upgraded to 2.5 TB using Hardware RAID 0. Tivo HD is the first model to break 2.2 TB barrier"

I think he has said over in the Tivo Upgrade Center here on the community forums what specific hardware he was using, but I do not recall.


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## HDTiVo (Nov 27, 2002)

HDTiVo said:


> I've also managed to get my prior Mirrors (Netgear SC101) to stop running. The mirrors keep breaking, so its useless for now. I didn't see anything on netgear's site that helped find the problem and haven't had time to call.


How does this One Touch RAID 0/1 1.5TB at $430 sound as a replacement connected via USB instead of the network for my TTG server?

One thing I'd like is automatic rebuilding of the RAID 1 arrary if a drive is replaced, which I don't see mentioned.

http://shop2.outpost.com/product/5031325?site=sa:Hard Drives Memory:Spot1

Perhaps a second Quattro would be better @ $465 because of the RAID5 space advantage and the use of 4 smaller cheaper drives instead of 2 larger expensive ones.


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## HDTiVo (Nov 27, 2002)

This page from Buy.com shows a couple of RAID drives in the price range of the Quattro that have eSATA II capability - Iomega (RAID1) and Cavalry (RAID5.)

http://www.buy.com/cat/raid-external-hard-drive/65152.html

After that, it looks like things are in the $1400 and up range. 

Other items to check out - RAID5 & eSATA II:

Micronet SR4 1.0TB eSATA RAID External Hard Drive - 2-Port eSATA PCI-Express, 7200, eSata ; also 2TB version for ~$230 more.

Beyond Micro DriveZilla 2TB External Hard Drive - 4 x 500GB, 7200, SATA MultiLane, External Storage Center (Drives included) - not sure about eSATA port. Port looks different.


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## TexasGrillChef (Sep 15, 2006)

HDTiVo said:


> That is much nicer than the Drivestation Quattro.
> 
> How do I find this product?
> 
> Thanks.


http://readynas.com/products/products_details.php?name=ReadyNAS NVPlus

ReadyNas NV+ (Infrant Technologies)

Download the Manual & check out all of its cool features.

I love this unit, it has UPnP AV server capabilities, X-Raid, USB HD Backup built in, And if you plug it into a UPS with USB connections. It will auto shut down when power fails as well.

Very nice unit!

It is capable of 3TB maximum using 4 - terabyte Drives

TGC


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## turbovr6 (Sep 1, 2004)

http://www.lacie.com/us/products/product.htm?pid=10951

Would this unit do the TivoHD justice? Price is a little steep but high quality


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## HDTiVo (Nov 27, 2002)

turbovr6 said:


> http://www.lacie.com/us/products/product.htm?pid=10951
> 
> Would this unit do the TivoHD justice? Price is a little steep but high quality


That is also eSATA I like the Quattro, so I'd be cautious about it. But what is cautious? Unless someone plugs one into a THD we don't know with any of these.

The auto rebuild, hot spare and hot swap features are niceties though.

Something else I wonder is whether any of these RAID systems allow drive *expansion via auto rebuild*. In other words, you replace a smaller disk with a bigger one and it rebuilds into a larger drive. That way one could incrementally increase storage. The other side of that is how these devices handle *unequal drive sizes*. Would be nice to take advantage of more than the lowest common denominator.

The X-RAID technology seems to anticipate the above...
http://readynas.com/products/products_details.php?name=About X-RAID


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## HDTiVo (Nov 27, 2002)

TexasGrillChef said:


> http://readynas.com/products/products_details.php?name=ReadyNAS NVPlus
> 
> ReadyNas NV+ (Infrant Technologies)
> 
> ...


That appears to be an NAS and therefore has an ethernet interface but no eSATA, so it would not be good for the TiVo; also it doesn't have a USB to PC interface, so it wouldn't fit my need on the PC since I am going to get away from the much slower network interface that I had with SC101.

The X-RAID features look very interesting as referenced above. An eSATA/USB combo unit that work with the THD could be interesting.


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## scoombs (Jun 23, 2002)

I have a ReadyNAS NV+ which is very nice, and it would be very good for the TTG server side of things.


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## jlib (Nov 22, 2002)

Sure giveaways that a RAID system will not work is if it says it comes with a RAID controller card as opposed to a simple eSATA card. If you see the term _multilane_ it also will not work. Still, a seeming likely candidate may simply not be bootable as I and HDTIVO have discovered. And some that will work pay no attention to noise attenuation in their design. So, though we can say what won't work with pretty good certainty it is a little more iffy as to what will work. Basically, someone just has to try a likely candidate.


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## HDTiVo (Nov 27, 2002)

I found these *5 Bay eSATA RAID* enclosures:

http://www.usb-ware.com/5-bay-esata-port-multiplier-enclosure.htm
$429 ; uses SI3726

http://www.usb-ware.com/venus-esata-hardware-raid-enclosure.htm
*$249*; Uses SI4726

http://www.usb-ware.com/esata-hardware-raid-enclosure.htm
$439; Uses SI4726

The main page with a bunch of these products is :
http://www.usb-ware.com/external-sata-products.htm

The $249 Venus is cheap enough that 5-500GB drives @$110 put it in the same price range as the 4-bay Buffalo 2TB Quattro.. not bad.

Anyone familar enough with these systems to judge whether they are worth a shot for the THD?

There was a post somewhere that mentioned SIxxxx model # and whether it likely would work. 

For my part, the big thing I would like beyond actual compatibility is the ability to put larger disks in over time and have the system rebuild to larger and larger size transparently. Otherwise I am not sure how one would get from say a 2.5TB system to a 5TB system easily with only one enclosure.


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## 1283 (Sep 8, 2000)

None of them would work. 3726 is JBOD only without RAID. 4726 supports RAID 0/1/10, but it requires the host software to initiate rebuild.


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## jlib (Nov 22, 2002)

Another thing to avoid are systems that require a specific eSATA card. It needs to work with any standard eSATA port. You don't want to see: _"Requires a SATA host controller that supports port multipliers."_


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## HDTiVo (Nov 27, 2002)

c3 said:


> None of them would work. 3726 is JBOD only without RAID. 4726 supports RAID 0/1/10, but it requires the host software to initiate rebuild.


Are you sure about that. SI's product sheet says:



> The SiI 4726 works with any Serial ATA compliant host port, although some features such
> as JBOD access require a port multiplier aware host controller such as SiI 3124-2 or
> SiI 3132. For more details, please contact your local Silicon Image sales representative.


http://www.siliconimage.com/docs/SI_4726_SteelVine Storage Processor.pdf

This is becomming a frustrating search.


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## andyw715 (Jul 31, 2007)

this would be nice if it were eSATA

www.drobo.com

basically x-raid as desribed above.

hot swap drives, add storage space on the fly


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## scoombs (Jun 23, 2002)

HDTiVo said:


> For my part, the big thing I would like beyond actual compatibility is the ability to put larger disks in over time and have the system rebuild to larger and larger size transparently. Otherwise I am not sure how one would get from say a 2.5TB system to a 5TB system easily with only one enclosure.


RAID just does not support the transparent growth you are looking for. You can mix drive sizes in a RAID, but it will always step down to the lowest common denominator. If you have a 5-drive RAID with four 1TB drives, and a single 250GB drive, then the RAID will consider them to be five 250GB drives.

The xRAID technology you referenced earlier does have a growth potential, but it is only a re-build on the fly...the volume will not offer you the new increased space until all of the drives have been swapped out to allow the RAID to see the higher lowest common denominator mentioned above. Traditionally, one uses a backup and restore method to grow a RAID volume from size-A to size-B.

I think you can add storage to any enclosure with free slots including the drobo (though it claims it does not use RAID, and handles it differently), but it would have to be addressed as a separate volume, because a RAIDed volume has the limits described above. And for a Tivo, adding an additional volume does not help since it will only address a single volume per "drive".


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## 1283 (Sep 8, 2000)

HDTiVo said:


> Are you sure about that.


100% positive. 4726 does work with any SATA controller. However, when a rebuild is needed, it has to notify the host software about the error, and the host software has to tell the 4726 to start the rebuild. There is no such host software on the TiVo, so the 4726 has no rebuild functionality.


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## HDTiVo (Nov 27, 2002)

c3 said:


> 100% positive. 4726 does work with any SATA controller. However, when a rebuild is needed, it has to notify the host software about the error, and the host software has to tell the 4726 to start the rebuild. There is no such host software on the TiVo, so the 4726 has no rebuild functionality.


Shoot.

The lowly Quattro seems to rebuild on its own just fine.


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## greg_burns (May 22, 2004)

Was looking through and old MaximumPC mag tonight and ran across this device. Made me think of this thread.

http://www.norcotek.com/DS-500.php

Would it work? 

P.74
http://www.maximumpc.com/article/april_2007_hardcore_hardware_head_to_head


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