[CentOS] openfiler (was: using CentOS as an iSCSI server?)
John R Pierce
pierce at hogranch.com
Tue Oct 20 23:04:49 UTC 2009
> Network RAID – only available from HP
Fantasy ideas (eg, I've only thought of this and never tried it). YMMV,
caveat emptor, objects in mirror may be closer than they appear, etc etc.
1) two ISCSI servers, each with identical storage. each offers the same
sized iscsi target to the host. the host uses mdraid 1 to mirror these.
2) two ISCSI servers, each with identical storage, configured as
active-standby cluster, using conventional cluster management software.
active 'master' replicates block storage to 'slave' using DRBD.
with 1) there's questions of how well the mdraid will recover from
situations where one storage server is offline for some period. I'd feel
much warmer about this if there was block checksumming and time stamping
in the raid ala ZFS.
with 2) there's write fencing issues I'd be uncomfortable with, on a
fenced write, you'd not want to acknowlege operation committed until the
drbd slave has flushed its buffers.
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