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RAID Boxes Run Riot

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March 23, 2007 9:49:34 AM

External storage appliances represent an excellent upgrade path for local storage. We looked at two RAID-based solutions from easyRAID and Sans Digital. Unfortunately, increased performance goes hand in hand with annoying decibel levels.

More about : raid boxes run riot

March 23, 2007 11:32:17 AM

Man I couldn't believe how much faster eSATA was than Firewire. I suppose I should have seen that coming, but I've not paid enough attention to eSATA in previous reviews. This was very eye-opening for me; thanks for writing this excellent article!
March 23, 2007 11:35:32 AM

I use the Buffalo Terastation and am very happy with it. Low noise and simple to set up.

Terrastation
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March 23, 2007 12:22:44 PM

An informative and readable article.

However, if I may make one correction: In describing eSATA and SAS external options, you say that SAS can be used to hook up arrays of drives while eSATA allows only one drive per cable. This is inaccurate. eSATA multilane is available now, and I use it daily. The Sonnet Fusion 500P is an example of an external eSATA device that hooks up 5 hard drives to your computer using only one eSATA cable. It does not present the drives as one array either - you see 5 hard drives in the Windows device manager, and they are hot-swap also.

Getting multilane eSATA to work with Linux? That's another challenge entirely...
March 23, 2007 12:38:01 PM

Sata is the only way to go. I built a PC in the end as I couldn't find an external box that had anything near the performance I wanted (although a 4 drive version of sans digital box looks like it might be very good indeed).

I used a 3Ware 9650SE card and a RDC-400-SATA drive cage in the PC - and yes the fans screamed, so I put dropper resistors on them all and the drives are all still 40C or less). With 4 500Gb drives in raid 5 array I get:

read: 160Mb / sec
write: 155Mb / sec
random: 4.5Mb / sec

this is tested with Performance test from passmark running for 30 secs per test.

1.3Tb storage, 2Gb RAM (with 3 VM's permanently running), and less than 100 watts power consumption

eSata is very good for external drives on laptops too, If I run a VM on a USB disc on any of my machines (under windoze) it will usually crash within an hour. On an eSata disc it will run forever.
March 23, 2007 8:23:55 PM

So if someone were foolish and got 6 of those eSata RAID boxes, loaded each with 2 drives and ran RAID0, then connected the 6 boxes internally to a SATA RAID5 card and ran RAID5 on it, it would pwn, rite?
March 23, 2007 10:29:26 PM

Quote:
An informative and readable article.

However, if I may make one correction: In describing eSATA and SAS external options, you say that SAS can be used to hook up arrays of drives while eSATA allows only one drive per cable. This is inaccurate. eSATA multilane is available now, and I use it daily. The Sonnet Fusion 500P is an example of an external eSATA device that hooks up 5 hard drives to your computer using only one eSATA cable. It does not present the drives as one array either - you see 5 hard drives in the Windows device manager, and they are hot-swap also.

Getting multilane eSATA to work with Linux? That's another challenge entirely...


Multilane does not allow more than one drive to be connected per SATA channel. What you're thinking about is probably a SATA Port Multiplier. These devices will allow up to 15 drives to be connected per SATA channel, however, most Port Multipliers only have connections for 5 Drives at a time (or less). Multilane is only a means to 'bundle' more than one SATA cable, into one large cable (IE, it is externaly one large cable, but inside are 4 cables for 4 HDDs, or 4 SATA connections, inside the enclosure / connected machine, there are still 4 single connections).

Port Multipliers also need a compatable HDD controller, to enable FIS based switching, which is usually a SIL 3132 or equivelent (SIL 3114, and the newer SIL 35xx controllers, I beleive). What FIS switching does, is enable the drives to work at full capacity while sharing the same SATA connection. Without it, you could not run RAID ( unless perhaps in software, and this would offer terrible performance ). Read about it Here . Regardless, one drive only could be accessed at a time using using a Port Multiplier without a compatable HDD controller chipset.

SAS is much better, with a good controller card, and multiple expanders, you could hook up to 128 drives per controller. SAS is also very expencive, but if speed is what you need, SAS is the only real way to go. Also, finding good hardware for SAS can be a bit hard right now, and getting expanders, without buying an expensive rack, or 2.5 formfactor drive tray assembly is next to impossible ( if not impossible outright ). Now, when I say 'expencive', we're talking $200 for a single 15k RPM 36GB Seagate Cheetah, at least $300 for a cheap controller that only offers RAID 0,1,10, plus if you plan on using the newer mini 4x 2.5 drive from 1x5.25 drive racks (with expander), add another few hundred into the mix). So, we're talking ~$500-$700 for a single drive ! The newer SAS Cheetahs that offer 300GB storage space, $1200 for a single drive only !

Port multipliers are an OK solution for the home envoirnment, but keep in mind that the RAID achieved handled using this technology is currently software only ( Even though, there are dedicated PM enclosures out there that handle the hardware internally, just dont expect them to be cheap). Also there are other solutions out there, Just need to google around, ask a friend on IRC, etc, to find out what is out there :) 

[EDIT]

I probably should have mentioned that using a SAS controller, you are not 'obligated' to use SAS drives, but in fact, you CAN use SATA drives with it. This means, with a SAS controller, and Expanders, you could also have up to 128 SATA HDDs connected to it. Pretty nifty technology . . .
March 25, 2007 12:32:11 PM

Thank you for paying attention to noise levels. It is a top criteria. Weight is also a deciding criteria for some applications. Firewire connectors have no locking mechanism and Macbooks have no esata so gigabit ethernet is the connector of choice. This allows the NAS to be placed in a separate room. The lightest in this category is the Lacie Ethernet Disk RAID and the fastest (and finally RAID 6) is the Thecus N5200BR. The Lacie Ethernet Disk RAID is a bit slow and has a noisy fan and the Thecus N5200BR is a bit heavier. It might be interesting to see an article on upgrading the CPU or motherboard in the Lacie Ethernet Disk RAID to improve performance. It might also be interesting to see how a user could install Hitachi 1TB drives in the Lacie Ethernet Disk RAID as this is not a supported feature. It might also be interesting to see an article on rebuilding the Thecus N5200BR in a new case to reduce weight or trying a lighter and quieter power supply and quieter fans. The Mac OS X also seems to have some instability with NFS, the Network File System and that is worth looking into. Users shouldn't be forced to use the Microsoft CIFS file system with its proprietary secrets and filename restrictions. The Lacie Ethernet Disk RAID weighs in at 5.45kg or 12 lbs.
March 29, 2007 12:58:41 AM

Tom's is a bit wacko on this topic.

1. "you cannot effortless [sic] hook them up to your PC" but must "install...or operate...inside external...enclosures"

Vendors sell ready-made units, pre-enclosed, USB cables sticking out the back. That's plug-and-play, brain-dead simple. Do-it-yourself means work, but it's not intrinsic.

Around here we run linux from portable USB hard drives and don't use IDE/SATA internals. Generally we spin them off with hdparm -Y. We can boot any PC and move our personal desktops from place to place. Yes we also do backups (one thing the IDEs are still good for).

RAID is the most complex arrangement of hdd's the average user might ever encounter. This is supposed to be an effortless solution? Not. "All you need to do is get adequate hard drives, install them, select your desired RAID mode and hook up the RAID boxes to your host PC before turning them on for the first time." IDE is simpler to install.

2. "hard drive storage is relatively...sensitive [with] a limited life span"

Flash (a form of solid state) has far worse lifespan problems. And file system corruption is more worrisome than hdd mechanical failure.

The mechanicals in PC hard drives are some of the most sophisticated and mature engineering exhibitions on the planet. By sophisticated I mean closed-loop servo circuits to manage the motions. By mature I mean decades of development and intense market competition. The damn things are so cheap nowadays a worried person can just replace them every 3 years with little pain.

3. "While semiconductors typically have a rather long life span"

Not flash. Of course, solid state is better than moving parts, as a general rule of thumb. But you pay for it (10x to 100x more per MiB) and anyway, it's quite the horse race in the PC storage universe.

Circuits are never 100% completely solid state. They have electrolytic caps which can leak, burst, and otherwise short, causing damage to the s.s. components. Apple and other vendors had recent major recalls (iMac) replacing motherboards because of bad caps.

Power supply failure is common too. Most PC supplies are switching supplies ("solid state"). Now which is more reliable - hdd's or power supplies?

4. "far from shockproof"

The old canard. Look, shop around. How about "withstanding 250 Gs of shock during operation and 900 Gs when not" ( www mobilemag dot com/content/100/334/C3401/ ) for under 100 bucks now (see www pricewatch dot com).

Nothing on earth is shock "proof." It's a question of engineering rating like anything else. What is the application, and how much g-shock rating does it need?

Besides, solid state is more sensitive to static electricity. Touch it just the wrong way, and zap.

5. Conclusion

For bizarre reasons Tom's wants to push RAID on people. I find these reviews useless. RAID is for server people who need the redundancy. What Joe Sixpack needs is backup. RAID is overkill.

If Tom's is worried about data loss, when was the last review of inline UPS? That would be nice. Lots of people have power dips and blackouts on their home lines. UPS makes a lot more sense than RAID.
March 30, 2007 7:27:53 PM

One of the things I keep an eye on in my home setup is power consumption. I have to assume those amazingly loud fans also eat power at quite a rate. I'd love to know what the idle power consumption is - since everything at my house is on 24/7, those little watts can add up....
April 10, 2007 1:58:23 AM

:?:
Ok, everybody is talking about the speed of eSATA versus Firewire. Are we talking here about Firewire 400 or Firewire 800? I am currently running external hard drives (LaCie 500gb) on Firewire 800 but need a larger backup package and am not sure if the upgrade to eSATA is worth it.

How important is "top speed" for data backup anyway if I don't need continuous backup (real time)? I can do my backup either in batches (coffe break ?) or automatically in off-hours?

I also understand that the "speed" is relative to what kind of data transfers you generally do. I am a photographer and my workfiles are often in the 2 to 3 gb size. I use the external drives both, for data storage/recall and for backup (separate drives) but use exclusively my internal drives while working on a file. Any specifics to this type of use? By the way, I am on a PC, if that makes any difference.

I know we can go to the moon, but my needs are very down to earth, although in specific ways no less demanding (time is money) Hope somebody can shed some light on this. Thanks
April 10, 2007 5:40:14 AM

Quote:
:?:
Ok, everybody is talking about the speed of eSATA versus Firewire. Are we talking here about Firewire 400 or Firewire 800? I am currently running external hard drives (LaCie 500gb) on Firewire 800 but need a larger backup package and am not sure if the upgrade to eSATA is worth it.

How important is "top speed" for data backup anyway if I don't need continuous backup (real time)? I can do my backup either in batches (coffe break ?) or automatically in off-hours?

I also understand that the "speed" is relative to what kind of data transfers you generally do. I am a photographer and my workfiles are often in the 2 to 3 gb size. I use the external drives both, for data storage/recall and for backup (separate drives) but use exclusively my internal drives while working on a file. Any specifics to this type of use? By the way, I am on a PC, if that makes any difference.

I know we can go to the moon, but my needs are very down to earth, although in specific ways no less demanding (time is money) Hope somebody can shed some light on this. Thanks


You can not really compare eSATA to any other external connection type, except perhaps external SAS, which would be way overboard.

Simply put, eSATA would offer the same speeds the drive would internaly, and is much easier to find hardware for, than finding *good* 1394b hardware, and eSATA also , if HDDs were capable of substaining high enough rates, stomp the ever loving bejsus out of firewire 800 ;) 

[EDIT]

Another fine point, I forgot to mention, cost is much less for eSATA stuff, pretty much, you buy a HDD, the enclosure, and an expansion slot conversion kit, that connects directly to a port on your motherboard, OR, you buy a motherboard that has an eSATA connector on it already. Either way, works the same, excpet perhaps, eSATA motherboards, tend to use HDD controller (usually a secondary controller), that do not always offer the best performance, but should not matter much, if you use a single drive only. If you use a SATA port multiplier (a whole different ballgame), then the HDD controller needs to support PMs, otherwise, at best case, you will only be able to use one drive at a time (means no RAID), or it will not work period.
April 10, 2007 8:10:52 PM

Yyrkoon,
thanks for shedding some light on the benefits and "how to" of eSATA. Do you, or anybody, have any comments to my second point: If I would really have a practical benefit under my use scenario (other than price, which is a good point). Apart from what I already stated, there is an additional application that occurred to me: to put a scratch disc on an external eSATA drive and I can see where that would really weigh in the favor of eSATA.

Thanks so far.
August 4, 2007 5:20:42 AM

just got my sans box working with two 750gb wd drives in raid-0, so here's some real life rap i thought i'd share.

- 1397gb formatted size
- this thing is solid metal, it gives a reliable feel and can likely take some transporting without giving in. i could step on it - how many external drives would you want to try that on?
- it runs cool, even while dumping a terabyte onto it. i'm going to put resistors on the fans to slow them down. it's not as noisy as i thought it would be (maybe they've changed the fans since the review), but silence is sweet.
- i only get 70mb/s via an express card SiI3132 interface on a laptop. a bit disappointed, i'm 30mb/s below tom! but with my previous thecus eSata box i also saw a big difference when plugging it to a dual xeon rig. & the 70mb/s is still twice the speed i get off the 5400rpm internal drive.
- to the linux gent above; well, some of us DO need speedy storage. i need it for video editing. besides, we all hoard more and more music, video, whatnot, and the faster it can move the better. even if it's just to clone your system drive for backup, 2 hours is more than 1 - and that's the time you won't be able to work.
- i wonder whether the internal interface supports NCQ or not - HD tune reports at the end of the eSata cable that it doesn't, but i wonder...
- temperature reading of the enclosure is available on the LCD display, but only when the drive is not talking to an OS. individual drive temperatures don't seem to travel via the eSata connection.

overall - so far so good.
!