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From: Chandra Seetharaman <sekharan@us.ibm.com>
To: dm-devel <dm-devel@redhat.com>,
	Linux SCSI Mailing list <linux-scsi@vger.kernel.org>
Cc: "Moger, Babu" <Babu.Moger@lsi.com>
Subject: SCSI Hardware Handler and slow failover with large number of LUNS
Date: Sat, 04 Apr 2009 14:30:36 -0700	[thread overview]
Message-ID: <1238880636.11478.8.camel@chandra-ubuntu> (raw)

Hello All,

During testing with the latest SCSI DH Handler on a rdac storage, Babu
found that the failover time with 100+ luns takes about 15 minutes,
which is not good.

We found that the problem is due to the fact that we serialize activate
in dm on the work queue.

We can solve the problem in rdac handler in 2 ways
 1. batch up the activates (mode_selects) and send few of them.
 2. Do mode selects in async mode.

Just wondering if anybody had seen the same problem in other storages
(EMC, HP and Alua). 

Please share your experiences, so we can come up with a solution that
works for all hardware handlers.

regards,

chandra


             reply	other threads:[~2009-04-04 21:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-04 21:30 Chandra Seetharaman [this message]
2009-04-06 14:44 ` SCSI Hardware Handler and slow failover with large number of LUNS Moger, Babu
2009-04-06 15:38 ` berthiaume_wayne
2009-04-06 17:47   ` Chandra Seetharaman
2009-04-06 17:59     ` SCSI Hardware Handler and slow failover with large number ofLUNS berthiaume_wayne
2009-04-06 15:43 ` SCSI Hardware Handler and slow failover with large number of LUNS Mike Christie
2009-04-06 18:21   ` [dm-devel] " Chandra Seetharaman
2009-04-06 18:54     ` Mike Christie
2009-04-06 20:09       ` [dm-devel] " Chandra Seetharaman

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