> From: Mathieu Simon [mailto:[email protected]] > > > I thought the ZFS mirror on separately hosted iscsi targets was going to be > > a > > great idea ... it turns out it's only great at destroying your pool... > > iSCSI is not a shared storage and if you write to the same disk/lun from 2 > initiators without "something in between" like DRBD (Linux), AVS, or > HAST (FreeBSD) > things are really expected to cause problems or call other evil dragons. :-)
Understood - But that's not the problem. When I have two OI machines that can both see the same iscsi targets, they're aware of themselves enough to prevent two systems writing the disks at the same time. If you have a pool imported on one system, and try to import it on the other system, it says "currently in use by another machine" or something. You can only override by force-importing the pool. This is enough to prevent two systems both writing to the same pool. Each pool will only be imported by one OS at a time. The problem is: If one of the targets reboots or becomes unavailable, it's not handled as removable storage. It's an IO error. And when the system comes back online, it doesn't just recovery gracefully, resilver, and move onward. It's a perpetual IO error. If the disk comes online, and maybe you have to "zpool clear" the faulted device, and then it resilvers... The pool is still unusable. My pool will actually appear to be in a healthy state; "zpool status" shows a healthy pool, but when an application tries to read/write the pool, I see scsi IO errors spewing into the syslog. Device timeout occurring, application hanging, and sometimes the host OS hangs. I have to permanently take the disks offline that were temporarily brought offline as a result of simply rebooting the iscsi target. ------------------------------------------- illumos-discuss Archives: https://www.listbox.com/member/archive/182180/=now RSS Feed: https://www.listbox.com/member/archive/rss/182180/21175430-2e6923be Modify Your Subscription: https://www.listbox.com/member/?member_id=21175430&id_secret=21175430-6a77cda4 Powered by Listbox: http://www.listbox.com
