topic 10G missing from SAS disk. in Operating System - HP-UX

10G missing from SAS disk.

Rahul Tiwari — Tue, 13 Jan 2009 07:52:52 GMT

Hello All,
Hi Gurus ,

We have new Rx boxes ( 2660,3600 and 6600) with 11 v3,some of them with internal P400 controller. on some of them root disk configured as IR volumes .sasmgr and diskinfo on some of them will show as follows :
---------- PHYSICAL DRIVES ----------
LUN dsf SAS Address Enclosure Bay Size(MB)
/dev/rdsk/c2t0d0 0x5000c5000c97c571 1 1 140014 çthis = 136G
/dev/rdsk/c2t1d0 0x5000c5000c9860cd 1 2 140014
/dev/rdsk/c2t2d0 0x5000c5000c98ae81 1 3 140014
/dev/rdsk/c2t3d0 0x5000c5000c986f31 1 4 140014
/dev/rdsk/c2t4d0 0x5000c5000c98299d 1 5 140014
/dev/rdsk/c2t5d0 0x5000c5000c98a655 1 6 140014
---------- LOGICAL DRIVE 7 ----------
Raid Level : RAID 1
Volume sas address : 0xa04dd81191b775d
Device Special File : /dev/rdsk/c2t6d0
Raid State : OPTIMAL
Raid Status Flag : ENABLED
Raid Size : 139898
Rebuild Rate : 0.00 %
Rebuild Progress : 100.00 %
Participating Physical Drive(s) :
SAS Address Enc Bay Size(MB) Type State
0x5000c5000c96c671 1 8 140014 SECONDARY ONLINE
0x5000c5000c97ece9 1 7 140014 PRIMARY ONLINE
=======================
# diskinfo /dev/rdsk/c2t1d0
SCSI describe of /dev/rdsk/c2t1d0:
vendor: HP
product id: DG146BB976
type: direct access
size: 143374744 Kbytes

bytes per sector: 512
The disk info( for the above 6 disk) will also show that the disk is of 136G only, however on the outer label on each of the disk it shows that disk is of 146G.Disk info for disk in vg00 also shows space as 136G.Except for disk in vg00, which are configured in raid 1, the remaining 6 disk is not configured in any raid.From each disk 10G is un-accountable for. The outer label on the disk and actual size as visible from OS is not matching , could you help me understanding this disparity. I am new to v3 and SAS terminology.

Re: 10G missing from SAS disk.

Eric SAUBIGNAC — Tue, 13 Jan 2009 09:21:19 GMT

Bonjour,

Disk capacity are always given in what I call commercial size, not technical size.

Commercial size is power of 10, technical size is power of 2.

146 commercial Go * 1000 / 1024 * 1000 / 1024 * 1000 /1024 = 135.97 technical Go, that is the 136 Go you can use.

Eric

Re: 10G missing from SAS disk.

Rahul Tiwari — Tue, 13 Jan 2009 10:27:45 GMT

GoodDay Eric ,

Thanks for the reply.
146 commercial Go * 1000 / 1024 * 1000 / 1024 * 1000 /1024 = 135.97

This is Ok .could you please let me know why 3 times *1000 /1024 ?

Thanks once again .

Re: 10G missing from SAS disk.

Eric SAUBIGNAC — Tue, 13 Jan 2009 10:55:42 GMT

1 commercial Go = 1000 x 1000 x 1000 = 1,000,000,000 octets
1 tecnical GO = 1024 x 1024 x 1024 = 1,073,741,824 octets

Re: 10G missing from SAS disk.

Rahul Tiwari — Tue, 13 Jan 2009 11:03:32 GMT

thank you very much Eric
:>)i should have revised my basics first :>).