Is Disk.Maxlun relevant to ISCSI?

[AndyShine]

I have an Equallogic ISCI SAN. I'm using the software initiator on most of my ESX servers( HP bl460c's) to connect to the storage. I'm just trying out a hardware initiator (QMH 4062) (which so far seems to be slower than the s\w initator!)

Whilst doing this work I came across the DIsk.Maxlun setting. It seems to be common to adjust this in a fibre-channel san environment to improve rescan and boot up times. I tried reducing Disk.Maxlun from its default 256 to 32 but didn't see much difference, hence my question.

Regards

Andrew

Message was edited by: AndyShine

[Lightbulb · Accepted solution]

From the "iSCSI SAN Configuration Guide":

(http://www.vmware.com/pdf/vi3_35/esx_3/r35u2/vi3_35_25_u2_iscsi_san_cfg.pdf)

Changing the Number of LUNs Scanned by Using Disk.MaxLUN

+By default, the VMkernel scans for LUN 0 to LUN 255 for every target (a total of 256 +

+LUNs). You can change the Disk.MaxLun parameter to change this number. This +

change might improve LUN discovery speed.

So the setting can be relevant to performance on ISCSI system, but changing it may have no impact.

[BUGCHK]

but didn't see much difference,

Last time I checked, the EqualLogic creates a new target/LUN combination for each new volume. So all iSCSI disks have a LUN address of 0 - and Maxlun does not work.

> can be relevant to performanc

Only for LUN discovery if LUN addresses 0..255 are being polled to check for existence of a LUN.