Now my questions are 1. Are the disks shown in Disk Mechs correspond to actual physical disks in XP array ? 2. Why is it that the alternate disk groups are having 2 and 3 CU:LDEVs - why not same number ?
I am aware command view is used to get info on XP arrays and only the LUNs made visible to the server are visible through xpinfo. But I do not have access to command view - with this limitation can anyone please provide help on the queries. The disks are 36 GB disks and each LUN is OPEN-8*2 (14014 MB). Please let me know if anything else is requried.
Thanks for your guidance. Only one thing - I had read somewhere that the 7+1P or ... are available with latest firmware for XP1024 , but not for XP256. Please can you confirm.
Yes you are right! RAID5 (7&1) is supported starting with XP128 / XP1024 and of course the XP1000 / XP12000.
Your configuration: RAID Group 1-1 is RAID1 and consists of physical disks R107 and R117. It presents 3 LUNs of 14GB to your HP-UX server: /dev/rdsk/c33t0d0 XP256 CL2A 00:00 14014 RAID1 1-1 /dev/rdsk/c53t0d1 XP256 CL1A 00:02 14014 RAID1 1-1 /dev/rdsk/c33t0d2 XP256 CL2A 00:04 14014 RAID1 1-1
Yes it seems as simple as you explained. But what I am not able to understand is that why the alternate raid-groups are having 2 and 3 CU:LDEVs ? why not 3 in all raid groups or why not 2 in all raid groups ? Also as per my understanding 36 GB disks are used. If you use 36 GB disks in a RAID1 we will have 36 GB usage apce in which I can create 2* 14GB LDEVs and still have 8 GB space unused. Also I cannot have 3 * 14 GB LDEVs in a raid group using 2 disks and RAID1. So how are 3 LDEVs possible in one RAID group ? The only way I can see is that if I can combine 2 raid groups then I can have 5 LDEVs of 14 GB amongst them thus only then it may be possible to see 2 LDEVs in one raid group and 3 LDEVs in next raid group. But then how does the xpinfo show the disk mechs as being different for both the raid groups - one raid group should show all the 4 disks as it is spanning across disks - if this is possible at all in the first place.
Please can anyone help on the above. How does it all work in reality. I have not worked on XP arrays, I am trying to check if any disks are unused and can be made available to be shifted to some other array.
Well, I can actually not fully understand your configuration! Can you provide a serial number of your XP256? I need the last 5 digits. I can then have a look at your HW configuration in the HP database.
Thanks a lot. The serial no - last 5 digits is 55289 for the XP256 array. Please let me know, If you want I can provide the full xpinfo output as well.
Ah, I see Your 36GB Disk Groups each are configured with 5x Open-8
Group 1-1 look like that CU-LDEV 0-00 0-01 0-02 0-03 0-04 Group 1-2 look like that CU-LDEV 0-05 0-06 0-07 0-08 0-09
In your XPINFO output above you only see the staring LDEV of a LUSE. It looks like your LUSEs consist of LDEV --------- Disk Group 0-00 + 0-01 -- 1-1 0-02 + 0-03 -- 1-1 0-04 + 0-05 -- 1-1 and 1-2 0-06 + 0-07 -- 1-2 0-08 + 0-09 -- 1-2 etc.
Peter is correct.. some of your RAID groups have LUSE (LUN expansion) -- which I think you]ve mentioned earlier youve LUSE*2.. you can check this out via SCSI inquiry (EMC's inquire command or other SCSI inquiry tools). I do not think xpinfo does justice and portrays what LDEVs have been LUSEd.
BTW, do not misconstrue LUSE'ing ldevs as a performance boost -- LUSE'ing ldevs is a means to carve up bigger LUNs. Note also that LUSEs are simply concats of your standard LDEVs.
I rarely use/request LUSEs. I Always use the host's volume manager to carve up bigger and better performing storage units (volumes?lvols) by striping them -- which is the best practice for XP/Hitachi arrays. (Yes XP arrays are rebadged Hitachi arrays).
OK. Just can you let me know is there limit to the LDEV size due to which its required to configure LUSE to get bigger LUNs ? - what is the limit ? What is the disadvantage of LUSE over normal LDEVs?
Under HP-UX I preffer using more LUNs/LDEVs and put them in a LVM Volume Group. Advantages: Performance - Each LUN has an IO queue Flexibility - You can add LUNs concurrently
The only disadvantage is that you have to manage more device files.
LUSE has two goals: Keep the numbers of LUNs low for larger volumes (Under Windows you need it if you need a big LUN)
You can build LUSE from 2 to 36 LDEVs.
To the Open-LDEVs
For the XP256 the following sizes are available: OPEN-3 2.4 GB OPEN-8 7.3 GB OPEN-9 7.3 GB OPEN-E 14.5GB OPEN-K 1.8GB OPEN-L 36.4GB OPEN-M 47.1 GB
