Simpler Navigation for Servers and Operating Systems - Please Update Your Bookmarks
Completed: a much simpler Servers and Operating Systems section of the Community. We combined many of the older boards, so you won't have to click through so many levels to get at the information you need. Check the consolidated boards here as many sub-forums are now single boards.
If you have bookmarked forums or discussion boards in Servers and Operating Systems, we suggest you check and update them as needed.
General
cancel
Showing results for 
Search instead for 
Did you mean: 

Timing cached reads performance fall DL585

Afanasiev
Occasional Visitor

Timing cached reads performance fall DL585

Die All,

I updating DB server from DL385 to new DL585, I have performance fall.
Tests show:

HP DL385
hdparm -T /dev/cciss/c0d0p1

/dev/cciss/c0d0p1:
Timing cached reads: 6426 MB in 2.00 seconds = 3215.23 MB/sec
HP DL585
hdparm -T /dev/cciss/c0d0p1

/dev/cciss/c0d0p1:
Timing cached reads: 1844 MB in 2.00 seconds = 922.00 MB/sec

RAID state id OK
hpacucli controller all show config

Smart Array P400 in Slot 9 (sn: PAFGL0P9SWY1MQ)

array A (SAS, Unused Space: 0 MB)

logicaldrive 1 (33.9 GB, RAID 1+0, OK)

physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 36 GB, OK)
physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SAS, 36 GB, OK)

I changed various BIOS settings, kernel settings and kernels, but it haven’t good effect.

What can I do to correct it? Thanks!
5 REPLIES
Vitaly Karasik_1
Honored Contributor

Re: Timing cached reads performance fall DL585

Do you have the same type of disks (SAS) and the same RAID config in both cases?
Afanasiev
Occasional Visitor

Re: Timing cached reads performance fall DL585

Yes, it's same disks
loco_vikide
Frequent Advisor

Re: Timing cached reads performance fall DL585

You might want to compare the Read / Write Cache settings on your Raid controller (Model ???) on DL385 server and the SMart Array P400 controller on DL585 server

Cheers
Ragu_3
Trusted Contributor

Re: Timing cached reads performance fall DL585

For the array type you are using, assuming that the controller is supported for GNU/Linux, changing your scheduler type can help.
Debian GNU/Linux for the Enterprise! Ask HP ...
Mike Stroyan
Honored Contributor

Re: Timing cached reads performance fall DL585

The performance of "hdparm -T" is not really a function of the disk or disk controller.
It measures transfer time from the RAM cache.
It is a measure of the RAM read rate.
A decrease in the reported "hdparm -T" rate may point to a problem with installing DIMMS in a proper high performance arrangement
Or it might be a side effect of NUMA vs. SUMA memory arrangement which will differ between a DL385 and larger systems like a DL585. You could check DIMM arrangement with dmidecode and experiment with changing the BIOS SUMA/NUMA setting.