> Hi, > I'm trying to resize a multipath map (an EMC Clariion LUN) but something > goes wrong with ioctl call. > After resizing LUN by EMC Navisphere, I rescanned four paths using: > echo "1" > /sys/bus/scsi/drivers/sd/<h>\:<b>\:<t>\:<l>/block/device/rescan > ... > I noticed (in /var/log/messages) that kernel "sees" new size only for > two > paths, surely the active ones (Clariion is an active/passive array). > Then, I trespassed LUN on the other storage processor and rescanned all > paths a second time: all sizes was updated. > But, re-running 'multipath -v2', I got: > # multipath -v 2 > device-mapper: reload ioctl failed: Invalid argument > I found no other way to make this work but umounting filesystem, > deactivating LVM and ran 'multipath -f ... && multipath -v2' (and then > other > regular LVM stuffs). > OS is Red Hat 4.5. > > About this, I found this message in archives: > http://www.redhat.com/archives/dm-devel/2007-August/msg00188.html > > Is it confirmed that online resizing with multipath is impossible? > > If yes, in my opinion, this is a serious limitation to a serious enterprise > use of Linux. I have used the following in the past when I needed to resize online. I have only tested this for the round robin selector but a similar method could also work for other selectors. #Started with the following dm table dmsetup table m500i_A_lun_4 0 157287936 multipath 0 0 1 1 round-robin 0 2 1 8:80 100 8:160 100 ###Used the following in a script to complete the resize dmsetup suspend m500i_A_lun_4 #Reload with one device removed and old size dmsetup load m500i_A_lun_4 <<EOF 0 157287936 multipath 0 0 1 1 round-robin 0 1 1 8:80 100 EOF dmsetup resume m500i_A_lun_4 dmsetup suspend m500i_A_lun_4 #Reload with one device removed for all other devices dmsetup load m500i_A_lun_4 <<EOF 0 157287936 multipath 0 0 1 1 round-robin 0 1 1 8:160 100 EOF dmsetup resume m500i_A_lun_4 dmsetup suspend m500i_A_lun_4 #Reload with all devices and new size dmsetup load m500i_A_lun_4 <<EOF 0 209717248 multipath 0 0 1 1 round-robin 0 2 1 8:80 100 8:160 100 EOF dmsetup resume m500i_A_lun_4 After the last step everything is able to see the new device size. I know this isn't an ideal solution but it might be useful for some people. Aaron Bergstralh -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
