Justin,

I do something similar, but not quite as complex.


I have a replicated (x2) Gluster volume where I drop thin-provisioned iSCSI 
volume files to be served up via tgtd on CentOS6.  I mount the Gluster volume 
locally on both Gluster servers (FUSE driver), then point the tgtd daemons to 
the image files.  I use this as a back-end for a VMware ESXi datastore, so I'm 
using the multipath iSCSI functionality of ESXi to handle the failover between 
the nodes.


I was previously doing this with DRBD/Pacemaker/Corosync, but ESXi freaks out 
when all paths to a datastore go down, and it takes ~2-5 seconds for the entire 
cluster stack to go down and come back up during an orderly failover (to say 
nothing of a catastrophic failover), so that model just didn't work for me.


I've since done some testing with just a simple VIP in Keepalived on top of 
Gluster using LIO and the libgfapi stuff on CentOS7, and that seemed to work 
great -- but I have some other incompatibilities with CentOS7, so I decided not 
to pursue that for this project -- maybe another one on the horizon.


I briefly tried testing the libgfapi driver on CentOS6 with my current 
production setup, but when I started the rebuild tgtd instance it gave my iSCSI 
LUNs different LUN numbers so my ESXi cluster didn't recognize them as 
different paths to the same LUN.  I couldn't be bothered to work out the reason 
for this change, so I just switched back in the meantime.  I will probably play 
with it a bit in a test environment when I have time -- the libgfapi stuff 
should be faster and more efficient than going through the FUSE stuff.


What would the Pacemaker CRM handle for you, besides a shared VIP?  Would you 
want it to start/stop the iSCSI target daemon as well?  (If so, why?)  Is there 
any reason to use a full CRM for this versus a simple VIP in something like 
keepalived?


Good luck, and let us know how you get on!


Regards,

Jon Heese



________________________________
From: [email protected] <[email protected]> on 
behalf of Justin Chin-You <[email protected]>
Sent: Monday, April 20, 2015 10:14 PM
To: [email protected]
Subject: [Gluster-users] GlusterFS with iSCSI and PaceMaker

Hi All,

I'm new to Gluster and I'm trying to work through some test configurations.

What I am trying to do is use Gluster to create a mirrored and scalable storage 
array. My plan is once I setup Gluster is to then export the GlusterFS via an 
iSCSI interface which will have an Active/Standby failover managed via 
Pacemaker.

I am curious if anyone has tried anything similar and if you have what iSCSI 
driver are you using.

Thanks,

Justin
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