These are notes on some experiments setting up hardware RAID on the MSA1000 and accessing the storage space under Linux. This MSA1000 holds five 146,8GB hard drives. We’ll attempt to configure a LUN with a RAID5 disk set comprised of four drives plus a spare. Detailed information on RAID level 5 can be found at: http://en.wikipedia.org/wiki/Redundant_array_of_independent_disks#RAID_5 At first, no units are configured on the MSA1000. Accessing the CLI as outlined in a previous post, we can take a look at our disk set:
CLI> show disks Disk List: (box,bay) (bus,ID) Size Units Disk101 (1,01) (0,00) 146.8GB none Disk102 (1,02) (0,01) 146.8GB none Disk103 (1,03) (0,02) 146.8GB none Disk104 (1,04) (0,03) 146.8GB none Disk105 (1,05) (0,04) 146.8GB none
Using the add unit command, we create the aforementioned unit using all four disks plus a spare:
CLI> ADD UNIT 0 DATA="Disk101-Disk104" SPARE="Disk105" RAID_LEVEL=5
Now we have a unit:
CLI> show units Unit 0: In PDLA mode, Unit 0 is Lun 1; In VSA mode, Unit 0 is Lun 0. Unit Identifier : Device Identifier : 600805F3-001828E0-00000000-68460002 Cache Status : Enabled Max Boot Partition: Enabled Volume Status : VOLUME OK Parity Init Status: 10% complete 4 Data Disk(s) used by lun 0: Disk101: Box 1, Bay 01, (SCSI bus 0, SCSI id 0) Disk102: Box 1, Bay 02, (SCSI bus 0, SCSI id 1) Disk103: Box 1, Bay 03, (SCSI bus 0, SCSI id 2) Disk104: Box 1, Bay 04, (SCSI bus 0, SCSI id 3) Spare Disk(s) used by lun 0: Disk105: Box 1, Bay 05, (SCSI bus 0, SCSI id 4) Logical Volume Raid Level: DISTRIBUTED PARITY FAULT TOLERANCE (Raid 5) stripe_size=16kB Logical Volume Capacity : 420,035MB
When initially powered on, the MSA1000 will detect host connections and assign them the default profile of DEFAULT. This profile must be changed to Linux using the ADD CONNECTION command:
CLI> ADD CONNECTION RX1600-1 WWPN=210000E0-8B004E53 PROFILE=LINUX
If all works out well, upon reboot the Linux hosts connected to the MSA1000 will then see the disk array as a single /dev/sda device, just like a regular SCSI disk. This device can then be partitioned or otherwise mangled at will. In our case, we’ll be deploying a Linux LVM solution on top of it, probably with using different filesystems for different logical volumes.