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ICH10R and Velociraptor Raid issue

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October 30, 2010 2:19:10 PM

Hello!
i have an asus rampage III extreme, a vertex2 ssd, and 2 velociraptor 450gb sata3.
I have win7 professional installed on the ssd, connected to intel sata controller.
I connect the 2 velociraptors to the intel controller, too, and set up a raid1 volume (using intel utility).
If i run ATTO benchmark, i have a very strange result, on the raid1:



I've re-installed win7, moved the ssd to the sata3 controller, changed 3 different versions of intel drivers... nothing changed.
Can somebody tell me what is wrong?

Thanks.

Andrea.
a c 127 G Storage
October 30, 2010 11:56:06 PM

Use CrystalDiskMark.

Note that if you have Intel 'write caching' option enabled, many benchmarks will produce odd results.
November 2, 2010 12:54:16 PM

hello,
thanks for reply.
here's the crystal result:



it looks like there is something wrong with seq read.

About the "write cache" i'm not sure of what is the option you mean.
Anyway, should the write-cache affect the seq read?

Thanks

Andrea.
Related resources
a c 127 G Storage
November 2, 2010 2:09:12 PM

Hm you're running RAID1; it could be that Intel doesn't have such great read throughput in RAID1. If you can, test with a RAID0 volume and bare disks without RAID as well. If that gives you proper reads, then this is what the Intel driver is capable of.

But the random I/O looks very good, particularly the random 4K QD32 read score likely is enhanced by RAID1.
November 2, 2010 7:07:23 PM

This is the result of a RAID0 volume:



This is the result of one-single-disk (without raid):


a c 127 G Storage
November 3, 2010 10:56:13 AM

Looks fine to me, so lower read score in RAID1 is due to Intel's way of doing RAID1; not really a problem. The speeds of single configuration and RAID0 look excellent.
November 3, 2010 11:03:02 AM

so, do you suggest me NOT to use raid1 on Intel ICH10R ?
If so, i have 2 options:
- RAID 1 with Marvell sata3 onboard controller (i've read not funny things about it)
- Mirroring with Windows 7 "Dynamic Disks" (somekind of a software-raid managed by OS)

What do you think?
a c 127 G Storage
November 3, 2010 11:40:47 AM

Marvell RAID controller generally has much poorer driver support; using it over the Intel controller is not recommended; the Intel controller is the best controller. Even 6Gbps SSDs would be faster when connected to 3Gbps Intel RAID controller, rather than 6Gbps Marvell controller with their RAID drivers. This has nothing to do with hardware but everything with the quality of their drivers.

If you ask my opinion, mirroring is pointless:
- RAID1 is not a backup
- you still need a backup to protect your files
- filesystem damage will damage the mirrored version as well
- problems with RAID drivers affects the mirror as well
- accidental deletion and corruption of files (virus?) is something RAID1 cannot protect against

RAID1 is great for uptime; when a piece of hardware fails and the computer needs to continue running. But for home users, RAID1 has been synonymous with a backup; but it isn't! It makes much more sense to not use RAID and use the second HDD as REAL backup instead, preferably in another physical system on the LAN. For example, the computer upstairs in your bedroom, or something similar. That get's you a REAL backup, while it needs the same amount of hardware. Thus, a RAID1 might not be that good for home users, as it is often used to replace a real backup. But a real backup protects against many more dangers than RAID is capable of.

So splitting RAID1 and connecting one HDD to another computer on the local network (in your home) would be an easy yet effective setup, which should work much better in protecting against dataloss. In that situation, HDD1 and HDD2 are totally unrelated to eachother, while in RAID1 they are both being controlled by the same piece of technology, which can fail, causing both disks to lose their function.

Scores without RAID look very good to me, for a HDD at least.
November 3, 2010 12:04:47 PM

thank you for attention, i know what is raid technology, and i know its limits. In fact, i have a NAS QNAP TS559 for backup...
So, i would like to do the raid volume anyway....
That said, what do you think about win7 mirroring solution?

thanks
a c 127 G Storage
November 3, 2010 1:22:52 PM

Don't want to be rude; but why would you want mirroring?

You bought your Velociraptors for performance reasons, i assume? If you have a backup, and you maintain it well, the consequences of losing the data on your Velociraptor disks is very low, just causes you some trouble, assuming the backup is setup properly and syncs regularly.

So if reliability is less of a concern, you can focus on performance and run your Velociraptors in RAID0 for extra performance, which should be noticeable in a few situations even on Windows 7 which has excellent caching and uses Superfetch to less rely on random I/O performance on the system disk.

So if you want speed and you think you can rely on your backup, then you may consider RAID0 instead. Otherwise, why not keep two separate Velociraptors without RAID, and copy some stuff from the first to the second as (additional?) backup. That still leaves you the possilibity to install application X to disk 1 and app Y to disk 2. Not sure what apps you run but for example Photoshop can use separate HDDs quite well (one primary, one scratch disk). So this also gets you a performance benefit.

So try to find out what your priorities are, and whether mirroring succeeds in doing that. If you don't mind lower performance, then still i would consider an onboard RAID1 much lower in security than a real backup; in some cases this can even be less reliable than a single disk without RAID1. But in other cases it helps you from a fully failed drive, without any data loss or recovery time. So it's all about priorities; what is important to you.
November 3, 2010 2:38:11 PM

Hi, don't mind about rudeness :) 
Well... to me, it's important reliability. First of all. Then, performance.
So, now i have:
- 2 SSD vertex2 (for OS and applications, as you said, not in raid, but as separate disks).
- 4TB of storage on my NAS (for long-term storage and backup)
- External USB disk for backup of very important data (backup of the NAS)
Usually, i work with lots of huge-sized RAW photos. So, i thought to place a "fast-mid-term-storage" to place the files downloaded from my CompactFlash cards. And keep the files there, until i have time to browse and select them.
I supposed that approx 500gb would be enough for this purpose, so i bought this 2 velociraptors, and put them in raid1.
I know that it could sound a "waste" of money, but I thuoght: "why should i buy a less performant disk, while i can get a velociraptor?"

Now, i'm looking for the best performance on this configuration.... and there is a bit of curiosity about how different solutions work ;-)
a c 127 G Storage
November 3, 2010 3:49:20 PM

If you already have a double backup (at least for your most important data) then you have all freedom to go for performance. If you want to avoid having to reconstruct the RAID and restore backup in case of a failure, then yes RAID1 could be less hassle. But personally if you ask me i would choose RAID0 since your backup solution sounds very solid! So to me it appears you already got the 'reliability' (data security) that you aimed at.

If you work with large RAW files this would be ideal for the speed bonus of RAID0, while RAID1 costs you a little performance instead. It's up to you though!

One thing i want to add: though HDDs can't do multiple things at once and thus doing so will cause them to switch from one to the other, which is very slow. But SSDs instead have no such limitation, and can process I/O in parallel. So for SSDs there's no special rule that says putting both system disk and storage on the same 'disk' (SSD in this case is bad; that's not the case for SSDs, you can use them for multiple tasks and do things simultaneously on the drive. You just need to enable AHCI to enable this behavior, as AHCI allows the use of NCQ which means the SSD can receive up to 32 outstanding commands.
!