Monitor NFS mount point IO performance

Problem:

I am configuring RMAN backup of my Oracle database and redirecting backup sets to Azure Blob Storage with NFSv3 access (quite a new feature for this time and needs to be tested). But I don’t know what will be the writing performance for this type of storage.

Solution:

One of the useful tools is nfsiostat, we will test it in this blog post.

1. After mounting Azure Blob Storage to my database node as /dbbackup mount point, instead of triggering RMAN backup I’d prefer dd command at this time:

$  dd if=/dev/zero of=/dbbackup/myfile oflag=direct bs=1M count=512000

2. Run nfsiostat with interval 1sec and monitor values:

[oracle@rac1 data]$ nfsiostat 1

marirmanstorage.blob.core.windows.net:/marirmanstorage/dbbackup mounted on /dbbackup:

   op/s	   rpc bklog
   0.11	   0.00
read:      ops/s    kB/s      kB/op.    retrans	 avg RTT (ms)	avg exe (ms)
	   0.000    0.000     0.000     0 (0.0%) 0.000	        0.000
write:     ops/s    kB/s      kB/op     retrans	 avg RTT (ms)	avg exe (ms)
	   18.000   18437.977 1024.332  0 (0.0%) 55.500	        55.611

For information, interval specifies the amount of time in seconds between each report. The first report contains statistics for the time since each file system was mounted. Each subsequent report contains statistics collected during the interval since the previous report

3. Cancel dd operation, you will also get information about the speed :

[oracle@rac1 dbbackup]$  dd if=/dev/zero of=/dbbackup/myfile oflag=direct bs=1M count=512000
^C
124+0 records in
124+0 records out
130023424 bytes (130 MB) copied, 6.85939 s, 19.0 MB/s

More information about nfsiostat can of course be found using man nfsiostat.