Adaptec 6405 RAID Controler Performance Issue

[Simon Bouchard]

FIXED: Adaptec 6405 RAID Controler Performance Issue

Hello everyone,Right now we're having performance issue with one of our node. VMs (KVM) are really slow, crashing, etc...Server Specs & Data

24 x Intel(R) Xeon(R) CPU X5670 @ 2.93GHz​

4 x SAS 6GB/s RAID5 Hardware (Adaptec 6405)96GB DDR3 1333MHz RAM

co-ve-001:~# uname -aLinux co-ve-001 2.6.32-6-pve #1 SMP Fri Nov 4 06:54:05 CET 2011 x86_64 GNU/Linux

co-ve-001:~# pveperfCPU BOGOMIPS:      141030.48REGEX/SECOND:      1067748HD SIZE:           94.49 GB (/dev/mapper/pve-root)BUFFERED READS:    242.79 MB/secAVERAGE SEEK TIME: 12.89 msFSYNCS/SECOND:     11.89DNS EXT:           66.98 msDNS INT:           1.01 ms (domain.com)

Read-cache mode: EnabledWrite-cache mode: Disabled (temporary write-through) Write-cache setting: Enabled (write-back) when protected by battery/ZMMPartitioned: YesProtected by hot space: NoBootable: YesBad stripes: No

co-ve-001:~# dd if=/dev/zero of=output.img bs=8k count=256k262144+0 records in262144+0 records out2147483648 bytes (2.1 GB) copied, 3.27609 s, 656 MB/s

co-ve-001:~# dd if=/dev/zero of=output2.img bs=8k count=256k conv=fdatasync262144+0 records in 262144+0 records out 2147483648 bytes (2.1 GB) copied, 47.8029 s, 44.9 MB/s

From a Virtual Machine

root@vm:~# dd if=/dev/zero of=output2.img bs=8k count=256k conv=fdatasync40746+0 records in40746+0 records out333791232 bytes (334 MB) copied, 20.5479 s, 16.2 MB/s

root@vm:~# dd if=/dev/zero of=output.img bs=8k count=256k62218+0 records in62218+0 records out509689856 bytes (510 MB) copied, 28.9495 s, 17.6 MB/s

 

[dietmar]

Your write cache is set to write-through - that should be write-back instead. Seems you do not have a BBU?

 

[Simon Bouchard]

Your write cache is set to write-through - that should be write-back instead. Seems you do not have a BBU?

Thanks for your reply, last night I've modified the cache setting and enabled it and everything is OK now.

co-ve-001:~# pveperf
CPU BOGOMIPS:      141029.42
REGEX/SECOND:      977842
HD SIZE:           94.49 GB (/dev/mapper/pve-root)
BUFFERED READS:    571.11 MB/sec
AVERAGE SEEK TIME: 4.36 ms
FSYNCS/SECOND:     940.02
DNS EXT:           69.86 ms
DNS INT:           1.01 ms (domain.com)

And the server is actually under heavy load. Writing on VM's filesystem at ~280 MB/s.

Thanks you!