I think the comments about this being the raid card may be right. The spec page of the 5405 quotes a data transfer rate of 3Gb/s per port. Note the small 'b'. 3Gb/s = 384MB/s, and that ties in pretty closely with the highest write rate seen in the test of 366.1MB/s.

From the figures, it seems pretty likely that the controller is the bottleneck here. It can't actually cope with the performance of these drives.

A 5805 card with two internal ports may have been a better bet.

Page 8/bottom:

"With just one exception, our four-drive X25-E Extreme array is the class of our iPEAK multitasking tests."

typo.

To be honest, it really doesn't make any sense to me why the these drives (and the ram drive) should be so close to the hard drives in the "real world" tests.

From personal experience, fast SSDs (when not randomly freezing) are mind blowingly fast compared to a velociraptor in general computer usage. Those benchmarks really don't reflect my experience at all.

That was 12 drives on a LSI 8708, using a poorly designed Supermicro SAS expander that only had one functional mini SAS port.

A mini SAS port gives you 12Gb of bandwidth that's is enough to pump out more than 1000 MB/sec in a 16-drives configuration. The SAS channel can't be the problem here. I know it because the expander of my company actually gives this performance with the decent LSI 8888ELP SAS board with 10K SAS drives.

Edit: Um, wow. Holy cow. Intel ICH7R and a P4 Extreme Edition as the testbed?

Can anyone say bottleneck?

This isn't really a fair review like we're used to seeing from TR. I'd like to see a RAID configuration using on-board RAID controllers as are typical with consumer boards.

I LOL'ed on several places - especially at but the card supports a whole host of other array configurations, including RAID 1, 1E, 5, 5EE, 6, 10, 50, 60, and 36DD . Ok, so maybe not the last one.

Keep up the good work - this was a great article!

you hit a bad raid card max transfer limit of 560.. my 4x vr300 do this..tweeked).. get a better raid card that has shown to do 800mb/sec

did you guys test this setup yourselves in real-world usage?

do those intel drives exhibit the random freezes that have plauged my attempts to use SSDs?

the problem with this guy is he doesn't think outside the box

how does he and we know how the other raid types will perform if he doesnt do and publish the benchmarks

believe it or not raid 5 works well with ssds, but you wouldn't know it from this piece of work

I personally was hoping to see a retest of the ACard with this controller. I am wondering if the on-board controller was holding it back, or not.

Nice Work. It is a shame you could not get the chance to bench RAID levels that would be intensive on the CPU (RAID 5 or greater).

The review just shows that how hardware RAID is slowly becoming more pointless to get when high RPM HDDs are getting replaced by SSDs. The memory buffer on true hardware controllers is meant to help reduce the latency associated with accessing data on different HDDs across the array. SSDs are so darn fast at random access speed that it practically eliminates the need for it. No CPU overhead is the last remaining benefit of hardware RAID. However, multi-core and super-fast CPUs do minimize its impact.

"Four X25-E Extreme SSDs in RAID 0 deliver by far the highest sustained throughput we've ever measured in HD Tach, and it doesn't matter whether you're reading or writing. We don't see anything close to a 4X increase in performance over a single-drive config, though."

As several others have mentioned, this may well be because of the I/O controller setup you chose for this test. Our own fairly extensive benchmarks on sustained read speed show that most modern motherboards equipped with 8-10 SATA ports can continuously and simultaneously run all ports flat out running simple Windows software RAID 0.

In other words, connect six drives each individually capable of 100MB/S transfer speed to six motherboard SATA ports (and/or SATA ports on a PCI-E controller card), stripe them with Windows Disk Manager, and you get almost exactly 600MB/S transfer speed (as measured by Microsoft Research Labs' DiskSpd, a benchmark utility tuned for massively parallel I/O arrays).

No need at all for 3rd party RAID controllers with RAID-0; the OS is about as good as you can get...

Geoff,

Can you re-test this with RAID 1 or RAID 10 instead?

In general, RAID 0 stinks for performance intensive situations. RAID 0 stinks because it uses stripping. You'll find the big disk vendors, like HP, EMC, etc. do not offer RAID 0 on their enterprise storage systems (except on their low-end SMB products which are NOT enterprise). They offer modified versions of RAID 5 (RAID S in EMC parlance), RAID 1, RAID 10 and a few other more exotic modes.

I suspect the controller really isn't to blame here. For SSD's and RAID 0 you need to tune the stripe size to that of the SSD. In RAID 0, if you have RAID 0 and the stripe size is 128KB (which is the default on system RAID cards), it means that unless the data size is > 128KB, the data sits on one disk or the other. You lose the benefit of read-ahead since one disk gets pounded with I/O and the other sits idle. Same problem for writes, if the data size is < 128KB one disk gets pounded. The controllers do try to spread it out, but...

If you re-test with RAID 1, you'll notice a big improvement in the read performance. This is because the controller can handle two simultaneous requests at a time (one per disk/SSD). If you have a 4 SSD RAID 1, you would be able to handle 4 reads at once. Writes of course are in parallel and should be equal to single disk performance for 2 disk/SSD sets.

And.. if you go RAID 10, you'll discover the performance should be eye popping, especially if you match the stripe size to the SSD block size. A "mirror of stripes" i.e. RAID 10 requires at least 4 disks, and gives ultimate data protection and performance since literally all disks are used in reads and writes.

As a BTW, you'll find many IT Storage Architects using RAID 10 (or their storage vendors equivalent) for their applications (think banking) since the need for a huge number of transactions and sustained performance. That's why they'd consider SSD's in the first place. IT Storage Architects will tend to use RAID 5 for bulk protection of storage at a reasonable cost. Before people go off on RAID 5 sucks, blah blah, remember true enterprise RAID arrays have 32-256GB of cache on them, so, RAID 5 performance isn't a issue. And... typically in enterprise frames (HP, EMC) the LUNs are mirrored internally and then a RAID 5 set is made out of those LUNs. The RAID 5 set is then presented to the outside world. RAID 5 over mirroed sets gives better performance and uses fewer disks than a RAID 10 set would give, lowering the cost of the storage in use.

For the small home server or low-end RAID 10 versus 1 does not matter, but as you have correctly noted, when SSD's are used in the enterprise, their performance, especially in that mode is king. Either RAID 1 or RAID 10 with those sweet SSD's you have will have them singing.

Bottom line, RAID 0 sucks.

The drawback to this test is that it doesn't give a good picture of the capabilities of 4 X-25 E drives in raid. My reasoning is that the drives experience a bandwidth bottleneck due to the limitation of one branched sata port which has a max bandwidth of about 300MB/s. If these drives were tested with a raid card which had multiple sata ports you would be able to take advantage of greater bandwidth. For example, a raid card with 4 sata ports( 4 x 300MB/S ) for a combined bandwidth which can more adequately take advantage of the pci express x8 slot which has a claimed bandwidth of 2GB/S.

Very interesting stuff. Real change is coming to the computer world. I can put all of my crap on a X25-M, if I wanted to replace my huge WD 640 SE16.

Of course, the only way to squelch the critics of the P4 are to take the exact same array and pop it into a Phenom II or Core i7 or something. Maybe you could do that as part of a review of the RAID controller instead of the drives, and then link the two stories. If you're going to review the controller please test it with more than Windows.

I don't care enough to complain, but when I see Windows reporting 50% load, I think about one core running full bore and the other totally idle in a dual core system. Not a complaint... just saying.

Can the wear leveling algorithms also add to the overhead of the raided SSD's? I would think it would only be micro seconds, but unlike platter storage, couldn't the data be written to differen't parts of the SSD every time?

The random access time measurement with only one decimal place to the right of the point is kind of pointless for flash and RAM based devices. Why not use a program that can measure it more precisely?

Also, since you get 560.5 average read for the RAID, which is not close to the 4x average read speed (236.5 x 4 = 946) you might expect, but the RAID is able to deliver 755.3 in burst mode (i.e., the bus is not the limitation for the aggregate read), it seems to me that the RAID card is meant to deliver aggregate reads up to 4x the average read of a normal hard disk (around 100). I.e., you picked the wrong RAID card to properly max out the performance of the flash disks. You probably need one that supports aggregation of 10 rotating disks.

All these requests for raid 1, 5, 10, reduced amount of drives, different test systems and a different controller but you are all overlooking the major issue here.

They weren't tested in my system.. in a undisclosed location in Mexico... with no expectation to ever get them back.. so screw you guys.

Thanks Geoff for the additional tests you ran from the original article, much appreciated.

Thanks a lot for testing these out with a decent raid controller, the peanut gallery (myself included) has been asking for this!

it would have been great though if you could have retested the ANS-9010 using the adaptec raid card though, as it would have been a much fairer comparison. OK it might not make any difference but i'd like to know.

Understand about the old P4 testbed- not ideal but yes it is preferable to have a standard platform to do comparisions. Could you please consider acquiring a (currently) high end raid controller as part of your replacement test bed to standardise any raid0 tests you do in future?

The article really does demonstrate that RAID0 has quite a limited value for desktop uses, and the returns are diminishing more and more as each device gets faster.

Overall: very interesting read over morning coffee, thanks!! :)

/. 'ed :)

would have been nice to see those mechanical drives in RAID 0...I am sure that long blue line would somehow be matched.

Hello, nice article! Interesting how so many tests didn't go in favor of the X25-E/RAID config, given that it displayed the best read and write throughput, with excellent access latencies. The later were a tiny bit higher than some of the other cards (not sure if that was within the std. error though), so maybe that explains it.

Anyhow, I'll chime in with my own suggestions of what else to test! :)

It would have been great to have been able to test the ANS-9010 with a decent RAID controller, but given that you guys probably sent it back already, how about testing the X25-E's using the ICH7R south bridge RAID controller? It would be interesting to compare the performance of the controllers, and beyond that it would certainly enable a more even comparison of the X25-E against the ANS-9010.

I would like to see a comparison of 15K SAS drives to this array, based on cost not number of units. It should be possible to make an 8 drive 15K SAS array for the cost of these 4 SSDs, is it faster?

Do SSDs still make sense from a cost / performance point of view?

Also, would something like a LSI MegaRAID 8708 produce better results? I have found that card to be particularly fast, and quite affordable.

Good to see some server hardware being tested.

Interesting article, thanks for posting this. I was very curious to see how four Intel SSDs would perform on Adaptec's best controller. Unfortunately that is just a huge disappointment!

On the bright side, Intel cut their SSD prices again today.

X25-E ~$425
X25-M $399 shipped @ Newegg

Interesting, a little disappointing, but so many more questions.
How do 4 raptors or decent 7200 rpm drives compare? - Seek times should go up as you wait for all four drives, but throughput should scale well?

How does the onboard raid compare? Is the card adding some additional latency because it is raid-0, or just because it is a card? cf, how does a single drive attached to the card do? And how does the DDR2 based disk do with the adeptec card?

How does the write caching on the card affect the infamous JMicron controller based cards cope with small random writes?

SSDs in a raid should scale near perfectly, are we just seeing the bottleneck move elsewhere in the system?

And is SATA 3 going to be enough? I thought SSDs used a RAID-0 style implementation internally anyway, so throughput would scale with density (or number of memory chips)

Dang my Macbook boots faster.

/bait.

Would it be possible to get a review of different RAID cards using this setup? (*Hint*Hint*) ;)

I really want to read this right now, but I have to get up for work tomorrow...where I'll read this article then. However, I'm sure I'm pretty sure I'll be dreaming about this tonight. *Best Homer voice* SSD's in raid *Homer drool*

Has there been any attempt to test different RAID block sizes on these SSDs?