I'm interested in this too.... I'm not sure how reliable iowait is as a metric on DRBD volumes - I've had it return more than 90% iowait on DRBD volumes doing a fraction of the iops that they're capable of at peak. Spindles on both sides were barely at 50% iowait, network and cpu well within limits.
It would be nice to have a process to isolate where DRBD thinks the bottlenecks are, at the moment it's a bit of a black box. James M On 17/02/11 06:41, Robinson, Eric wrote: > While performing a resync, iostat shows that nodeA (primary) is doing almost > all reads while nodeB > (secondary) is doing almost all writes, which is expected. However, I'm > trying to see the names > of the processes that are doing the reading and writing. I tried enabling > /proc/sys/vm/block_dump > and checking dmesg, but most of what I see in there is kjournald. Do DRBD > processes not show up in > kernel debug output? If not, how do I isolate the source of constant 25-50% > iowait on a computer > running DRBD? > > > -- > Eric Robinson > > > > > > > > > > Disclaimer - February 16, 2011 > > This email and any files transmitted with it are confidential and intended > solely for > *[email protected]*. If you are not the named addressee you should > not disseminate, > distribute, copy or alter this email. Any views or opinions presented in this > email are solely those > of the author and might not represent those of Physicians' Managed Care or > Physician Select > Management. Warning: Although Physicians' Managed Care or Physician Select > Management has taken > reasonable precautions to ensure no viruses are present in this email, the > company cannot accept > responsibility for any loss or damage arising from the use of this email or > attachments. > > > > _______________________________________________ > drbd-user mailing list > [email protected] > http://lists.linbit.com/mailman/listinfo/drbd-user The information in this e-mail and any attachment is confidential and is intended only for the named recipient(s). The e-mail may not be disclosed or used by any person other than the addressee, nor may it be copied in any way. If you are not a named recipient please notify the sender immediately and delete any copies of this message. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden. Any view or opinions presented are solely those of the author and do not necessarily represent those of the company. _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
