James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, 2008-01-23 at 16:32 -0800, Chandra Seetharaman wrote: > > Subject: scsi_dh: Add support for SDEV_PASSIVE > > > > From: Chandra Seetharaman <sekharan@xxxxxxxxxx> > > > > This patch adds a new device state SDEV_PASSIVE, to correspond to the > > passive side access of an active/passive multipathed device. > > Really, no; this isn't right. The state field of a SCSI device is for > the SCSI state model. Passive might be a valid device mapper state, but > it's not a valid SCSI state. If these patches can't work except by > mucking with the SCSI state model, there's some layering problem > elsewhere that needs sorting out. > It is actually a valid state for this device and a number of other devices that have passive / active controller. There are differences in response capability (i.e., media access commands) on certain sds until a fail over command is given. The response behavior difference along with all the partition scanning and other commands that get generated during the probing of a device are what leads to the long boot times previously mentioned by Chandra. Since we have created a policy to remove the vendor specific multipath drivers that handled the aggregation of the paths into a single device we need some method to handle devices that are not fully capable, but are still expose to the upper layers. The patches are also addressing a long standing issue of sense data processing, but that is not related to the SDEV_* state comment. -andmike -- Michael Anderson andmike@xxxxxxxxxxxxxxxxxx -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
