Re: Ceph RBD - High IOWait during the Writes

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



for certain CPU architecture, disable spectre and meltdown mitigations. (be certain network to physical nodes is secure from internet access) (use apt proxy, http(s), curl proxy servers) 
Try to toggle on or off the physical on disk cache. (raid controller command)
^I had same issue, doing both of these fixed it. In my case the disks I had needed on disk cache hard set to ‘on’. raid card default was not good. (be sure to have diverse power and UPS protection if needed to run on disk cache on) (good RAID. battery if using raid cache improves perf.)

to see the perf impact of spec. and melt. mitigation vs. off, run: dd if=/dev/zero of=/dev/null 
^i run for 5 seconds and then ctl+c
will show a max north bridge ops.

to see the difference in await and IOPs when toggle RAID card features and on disk cache I run: iostat -xtc 2
and use fio to generate disk load for testing IOPs. (google fio example commands)
^south bridge +raid controller to disks ops and latency.

-Edward Kalk
Datacenter Virtualization
Performance Engineering 
Socket Telecom
Columbia, MO, USA
ekalk@xxxxxxxxxx

> On Nov 12, 2020, at 4:45 AM, athreyavc <athreyavc@xxxxxxxxx> wrote:
> 
> Jumbo frames enabled  and MTU is 9000
_______________________________________________
ceph-users mailing list -- ceph-users@xxxxxxx
To unsubscribe send an email to ceph-users-leave@xxxxxxx




[Index of Archives]     [Information on CEPH]     [Linux Filesystem Development]     [Ceph Development]     [Ceph Large]     [Ceph Dev]     [Linux USB Development]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [xfs]


  Powered by Linux