Florian Haas wrote:
Imported from Red Hat scsi-target-utils package.
+ daemon tgtd $TGTD_OPTIONS
+
+ # read the config
+ tgt-admin -e -c "${TGTD_CONFIG}"
Some short note here.
Rebooting a target is always a tricky operation, but is needed sometimes
(kernel upgrade, hardware upgrade, tgtd upgrade etc.).
Initiators which are disconnected will try to reconnect (in open-iscsi,
up to 120 seconds, by default) - which is good.
However with lots of targets configured, and with many initiators
connected to all these targets, there is a short "window" when the
initiators will want to connect, but tgtd will reply: "no such target
here". And the initiator will fail (filesystem remounted read only,
device offlined) - bad.
This one will start tgtd with no targets - any (re)connecting initiator
will receive a "target offline" reply - which is non-fatal, and the
initiator will still try to reconnect:
daemon tgtd $TGTD_OPTIONS
Now, as the first target is configured, tgtd will no longer reply
"target offline":
tgt-admin -e -c "${TGTD_CONFIG}"
As tgt-admin keeps adding the targets to tgtd, it is possible that an
initiator will try to reconnect to a not-yet-existing target (because
tgt-admin still runs) - this will fail the initiator for good.
Therefore, it is safer to start tgtd and configure the targets with
these commands:
daemon tgtd $TGTD_OPTIONS
tgtadm --op update --mode sys --name State -v offline
tgt-admin -e -c "${TGTD_CONFIG}"
tgtadm --op update --mode sys --name State -v ready
With just a few targets and few initiators connected, it's not very
likely to spot it.
But as you have ~50 or more targets, ~10 or more initiators connected to
these targets (making ~500 connections), it is relatively easy to spot.
Perhaps easy to spot with even less initiators/targets configured.
Similar is valid for "forcedstop".
--
Tomasz Chmielewski
http://wpkg.org
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