If you happen to have an old SAN which contains perfectly usable disks, you might experience that hooking these disks onto youe SAS HBA/Raid-controller won’t work out of the box. I recently pulled 11 disks from an old EMC AX-4 for reuse in a PowerEdge 720XD (10 disks for RAID-10 plus 1 hotspare and 1 SSD for CacheCade), and noticed that the disks had an unsupported formatting. I forgot to screenshot the info from my disks, so I snipped the info from http://pissedoffadmins.com/general/unsupported-sector-size-520.html
[ 86.717949] Vendor: IBM Model: IC35L146 CLAR146 Rev: R58A [ 86.717970] Type: Direct-Access ANSI SCSI revision: 03 [ 86.720959] sdb : unsupported sector size 520. [ 86.720966] SCSI device sdb: 0 512-byte hdwr sectors (0 MB) [ 86.722822] sdb: Write Protect is off [ 86.722828] sdb: Mode Sense: e3 00 00 08 [ 86.725797] SCSI device sdb: drive cache: write through [ 86.725908] sd 0:0:1:0: Attached scsi disk sdb [ 86.726103] sd 0:0:1:0: Attached scsi generic sg1 type 0
As can be seen – these disks had an unsupported sector size (520 vs the regular 512). In order to get the disks working I installed the sg3_utils on my CentOS machine.
Perform a scan and see the disks available for a sector size change
# sg_scan -i /dev/sdb: scsi channel=0 id=2 lun=0 Vendor: IBM Model: IC35L146 CLAR146 [rmb=0 cmdq=1 pqual=0 pdev=0x0]
As said – my output wasn’t exactly like this, but you get the idea… Then perform the sector size change
# sg_format –format –size=512 /dev/sdb
Vendor: IBM Model: IC35L146 CLAR146 peripheral_type: disk [0x0] Mode Sense (block descriptor) data, prior to changes: Number of blocks=573653847 [0x22314357] Block size=520 [0x208]
A FORMAT will commence in 10 seconds ALL data on /dev/sg8 will be DESTROYED Press control-C to abort
I had Seagate 600GB 15k disks, and I believe the formatting was close to 60 minutes per disk. I had 11 of these, and to speed things up I just did’em all in parallell 😉 The PERC complains about unsupported disks, but I imagine these disks will work just fine in our dev-environment.