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LSI 9271-8iCC Slow Read/Write

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  • NAS / RAID
  • Storage
Last response: in Storage
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April 6, 2013 1:14:50 PM

We just got done finished setting up our new server, with a fairly high end array and were really put off by the results we got for reads/writes. First off, here is some specs:

2 x E5-2620's w/ SM board
8 x 2TB in Raid-10 for the main storage
2 x 120GB SSD in Raid-1 for ssd caching (cachecade)
LSI 9271-8iCC (with LSI recommended settings)

Here is what we are getting for read speeds:

/dev/sdb:
Timing cached reads: 16740 MB in 1.98 seconds = 8436.40 MB/sec
Timing buffered disk reads: 1338 MB in 3.00 seconds = 445.70 MB/sec

We are using the latest firmware, drivers and its the same on CentOS 6's 2.6.32 or mainline 3.8.xx

If I compare this to another one of our servers (Adaptec 5805Z, 6x WD RE4 1TB):

/dev/sda:
Timing cached reads: 25604 MB in 2.00 seconds = 12816.07 MB/sec
Timing buffered disk reads: 2136 MB in 3.00 seconds = 711.98 MB/sec

With more disks, faster memory and twice the amount I would expect higher figures.

Any ideas why we are getting such slow speeds?

More about : lsi 9271 8icc slow read write

a c 943 G Storage
April 6, 2013 1:36:14 PM

8 drives in raid 10 means you have two sets of 4 drives in raid 0 and those two sets are then mirrored to form the raid 10. For 4 drives 445mb/s does not seem too slow to me.

Which drives are you using in the raid 10?

I suspect the RE4's in the other server are in raid 5 or 6.
April 7, 2013 8:39:08 AM

Thank you for the reply.

1. We are using Western Digital RE4's in the LSI array as well.

2. For SSD's we are using MKNSSDCR120GB-DX7 for the cachecade in raid-1.

Again though, with more disks in our LSI array, more ram, faster ram, PCI 3.0, FastPath, CacheCade, we would expect to atleast get the same results of older and lower spec adaptec 6 drive array:

Adaptec 6 disk:

10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 13.8036 s, 778 MB/s

LSI 8 disk:

10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 23.4447 s, 458 MB/s
a c 943 G Storage
April 7, 2013 3:43:19 PM

You still are thinking the LSI as an 8 disk .. its not. Its a 4 disk raid 0 with another 4 disk mirror.

re4's avg about 110m/s reads & writes so... x 4 = 440mb/s

I don't see an issue and you cant compare to the adaptec until we know its configuration too.
!