1

Is there a way to analyze the IO wait on a iSCSI mount from the machine on which the iSCSI share is mounted?

I understand the local volumes can be analyzed, but, we have one particular directory on which the iSCSI storage is mounted. I'm interested in analyzing the I/O wait on this.

2

Yes,

The iSCSI "mount" is really presented to your machine as a block device.

From dmesg output...

scsi3 : iSCSI Initiator over TCP/IP
scsi 3:0:0:4: Direct-Access     NEXENTA  COMSTAR          1.0  PQ: 0 ANSI: 5
sd 3:0:0:4: Attached scsi generic sg3 type 0
sd 3:0:0:4: [sdc] Attached SCSI disk

So... df -h shows:

Filesystem            Size  Used Avail Use% Mounted on
/dev/sdc1             120G   58G   63G  48% /yum

As such, I can run normal I/O utilities and collect metrics on the /dev/sdc device.

# iostat -k sdc 2

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sdc               0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
          24.47    0.00    1.63    3.26    0.00   70.64

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