topic Re: 2x 80Gb X25-M G2 - To RAID or not to RAID... in Archive

2x 80Gb X25-M G2 - To RAID or not to RAID...

idata — Tue, 16 Mar 2010 14:10:18 GMT

Hello all,

I am relatively new to the forum and have read a lot of the posts, and they are quite informative. I have 2 x 80GB X25-M Gen2 drives. I am currently running them in RAID0 (hardware RAID).

After doing some reading in the forums, I understand that TRIM is not supported via RAID as it would require my RAID controller to support command passthrough - which none do currently (I have an EVGA x58 SLI Micro mobo - using the onboard controller).

I don't have a problem running the drives as two distinct 80GB drives and in turn gaining TRIM support. But my understanding is that RAID0 is a decent speed improvement even with SSD drives.

My use is primarily gaming and working with Photoshop type applications.

So I have a question, TRIM vs RAID0, which is better for overall performance?

Re: 2x 80Gb X25-M G2 - To RAID or not to RAID...

idata — Tue, 16 Mar 2010 15:22:54 GMT

Raid 0 does not help random read/ writes speeds at low queue depths and it adds latency on a hard raid array.

A lot of people think they are power users and therefore the queue depth will be high however even a power user is still only one person making demands on the storage system, which is very different to multiple people making simultaneous demands in a server environment.

People also forget that access time is so low with SSD's that the queue depth is kept lower than would be the case for a hard drive.

If you monitor your queue depth you will most like see that you queue depth does not go above one and if it does it only does it very briefly.

With regards to sequential speeds raid will improve performance, however most operations are random reads so this will only be a benefit in very specific circumstances.

I've had a soft and hard raid 0 set up with 2 x X25-E's and a single G2 set up. I can't tell the difference between those set ups with my usage patterns, which does not sound much different to what you describe.

Bottom line – unless you have a very specific requirement raid 0 is not going to make things any faster. Add to that the loss of TRIM and the higher risk of data loss with raid 0……

Re: 2x 80Gb X25-M G2 - To RAID or not to RAID...

idata — Tue, 16 Mar 2010 16:18:13 GMT

Thanks for the quick and very detailed and easy to understand response.

You indicate with a usage similar to mine - the RAID0 performance gain doesn't really offset the integrity offered via TRIM.

I will post my RAID performance figures and after un-RAIDing, the single disk performance.

Re: 2x 80Gb X25-M G2 - To RAID or not to RAID...

idata — Wed, 17 Mar 2010 13:52:01 GMT

redux wrote:

...

With regards to sequential speeds raid will improve performance, however most operations are random reads so this will only be a benefit in very specific circumstances.

Bottom line – unless you have a very specific requirement raid 0 is not going to make things any faster. Add to that the loss of TRIM and the higher risk of data loss with raid 0……

Hi Redux, so I un-RAIDed my drives and run them separately now. Running the same driver set, here are the performance differences according to CrystalDiskMark. The benchmarks are substantially different, even for random @ almost 2x.

RST - RAID0

--------------------------------------------------

Crystal Dew World : http://crystalmark.info/

--------------------------------------------------

Sequential Read : 601.346 MB/s

Sequential Write : 170.583 MB/s

Random Read 512KB : 392.803 MB/s

Random Write 512KB : 194.468 MB/s

Random Read 4KB : 22.136 MB/s

Random Write 4KB : 160.312 MB/s

Test Size : 100 MB

RST - NON-RAID

--------------------------------------------------

Crystal Dew World : http://crystalmark.info/

--------------------------------------------------

Sequential Read : 260.926 MB/s

Sequential Write : 87.771 MB/s

Random Read 512KB : 193.150 MB/s

Random Write 512KB : 85.668 MB/s

Random Read 4KB : 22.554 MB/s

Random Write 4KB : 57.624 MB/s

Test Size : 100 MB

Re: 2x 80Gb X25-M G2 - To RAID or not to RAID...

idata — Wed, 17 Mar 2010 14:49:03 GMT

Running RAID0 is great for people who love to look at benchmark results. The question is how much of a difference do you see in your computer operation? The other question is is it worth the risk? Personally, I prefer to use my other 160GB SSD to periodically create a system image in case of disaster. What do you have in case of disaster? I don't enjoy spending lots of time reinstalling Windows along with all my programs, data, etc.

Re: 2x 80Gb X25-M G2 - To RAID or not to RAID...

idata — Wed, 17 Mar 2010 19:08:14 GMT

As ambizytl states the real question is do you notice a difference? Below are AS SSD Benchmarks from a single drive and a raid 0 array.

Notice the 4k (QD1) results don't improve with raid 0? If I was getting any benefit from running two drives in raid 0 I would not have switched to a single drive. Some people will swear that raid 0 is much faster but from my experience at least it did nothing apart from inflate benchmark scores.

Let us know what your verdict is.

X25-E x 2 ICH9r Raid 0 128k stripe

X25-M 160GB ICH9