Mirror Write Speed

[chop]

Feel quite foolish, we bought the Mirror and Replication edition to do the following:

Server - ISCSI Target Host - Replication ISCSI Target Host

The replication was going to occur over 100mbs link to another campus. The problem we have is really poor write speed to the primary ISCSI Target, we have enabled async, caches on both sides. But it is still alot slower then a normal .img disk.

Is there anything that can be done, other then switch off the mirror and buy into something else!!!

[Max (staff)]

Hi chop,
What are the current modes for primary and secondary mirrors?
Have you tried to do some network tuning between the machines?

[chop]

Modes? I just created the mirror as stated somewhere in the forum and they are linked by a 1GBE vlan in async config.

First Mirror: write thru 2048mb cache

Second Mirror: normal no cache (have tried so many times to turn caching on at this point). When the mirror was created is was created with the same write thru cache config.

[chop]

ATTO test

Mirror Enabled

Untitled-3.gif (17.09 KiB) Viewed 414 times

No Mirror Enabled

Untitled-4.gif (15.43 KiB) Viewed 403 times

[Max (staff)]

What is the cache size you use on the primary host? and what is the cache mode you've set for the second mirror (not the image but the target you're selecting in the wizard when creating the mirror device)
Try to set the second mirror to Replication mode, this should increase the write performance, also the cache should be at least 128MB♠

[chop]

Primary Cache: 2048

Secondary Cache: 2048

Secondary Cache Target: 2048

Tried to set it to replication and when I check the settings after the mirror is created it always says Normal (No Caching)!!!

[Max (staff)]

That's strange, I can not reproduce this, the GUI does really show no caching, but the writes are about 60 MB/s and reads are @ 80-90 in an old demo lab. I think it's something with the allignment here...