Getting slow CIFS response on a filer

Doing a lot of snapshot operations on a filer can slow down the CIFS response even when sysstat -x 1 doesn't report a busy filer.


Check for high disk utilization with a perfstat, it so check your snapshot/snapmirror schedule

When your doing a lot of snapshot operations, for example all volumes every hour, the Container Block Reclaim scanner on the

filer could drain the filers performance.


The Container Block Reclaim (CBR) scanners: These scanners run on each volume after each snapshot deletion to return space back

to the aggregate. In other words there is a direct relation between the perfomance degradation and the snapshot schedules.


Default the CBR Scan process runs on a priority of 2000, by setting this option to 1 you can check to see of this solves any

performance issues with for example CIFS


How to set the CBR scan process to 1:

toaster>priv set diag

toaster*>wafl scan speed 1


You can set it back to its default by entering "wafl scan speed 0"


Note: You should not leave this process on a priority of 1, this is only usefull to check if the CBR scan process is draining you filers performance