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XP24000 and decision on luns size and mutipathing software

Domenico_8
Occasional Advisor

XP24000 and decision on luns size and mutipathing software

Hello,

We are busy to setup an extended Campus cluster using 2 X rx6600 and HP-UX 11.23.
Now we need to build the customer filesystems using the luns on the XP.(Lun size is 14.6 GB, and RAID 5,7D + 1P is used).We intend to use LVM mirroring and pvlinks.The filesystems to build are the following:

50GB to mount on oraexe
300GB to mount on oradata1
150GB to mount on orasave1
Now the questions are:

1. Do we need to use multipathing software(Advantage/Disadavantage) or pvlinks is just enough?(We have 2 FC 4GB/s used as primary, alternate path to connect to the SAN storage)
2.Which lun size (small one (14.6GB) or bigger one 29.2GB or 43.8GB or 58.4GB...) to use on the XP side in order to build the VG and LVs?What are the rules and impacts on the performance?
3.Do we need to use stripping?

Thanks in advance.




5 REPLIES
IBaltay
Honored Contributor

Re: XP24000 and decision on luns size and mutipathing software

Hi,
1. PVlinks is sufficient

2. Backend

the best is to give the LVM LDEVS across all available the Array groups
Front end
the best is to load balance the LDEVs across all available Front ports (Chip ports)

3. Striping is giving you the best performance

11.31 LVM
http://docs.hp.com/en/5992-4589/5992-4589.pdf

11.31/11.23 LVM
http://docs.hp.com/en/oshpux11iv3.html
the pain is one part of the reality
IBaltay
Honored Contributor

Re: XP24000 and decision on luns size and mutipathing software

one additional, it is good to have also some 4D+4D(RAID1) array groups for Oracle redo/archive logs...
the pain is one part of the reality
IBaltay
Honored Contributor

Re: XP24000 and decision on luns size and mutipathing software

>50GB to mount on oraexe (can be 7D+1P)
this can be e.g. 1 LDEV
>300GB to mount on oradata1 (can be 7D+1P)
this can be 4 LDEVS of 75GB if you have 4 paths or 8 LDEVs of 38GB if you have 8 paths
>150GB to mount on orasave1, the same as for the 300GB (4x38GB or 8x19GB)

the pain is one part of the reality
TTr
Honored Contributor

Re: XP24000 and decision on luns size and mutipathing software

1. PVlinks is sufficient but ensure that you alternate the device paths when you bring in the LDEVs in the volume groups.
The main difference between PVlinks and other multipathing software is that PVlinks always uses the primary path for i/o and the alternates as failover. So you have to alternate the two paths of each ldev in the two HBAs. This way you have a "manual" balance, half of the ldevs have primary on the first HBA and alternate on the second HBA. The other half ldevs have primary on the second HBA and primary on the first. The i/o in this setup is not split exactly 50/50 on the two HBAs but it is resonably close. With multipathing software, one virtual device path is used in LVM and it is translated to the two physical device paths. Then for i/o one or both of the physical paths are used, it depends on the multipathing software.
2. I would use 50-100GB LUN sizes. Consider using more than one volume for oradata, oradata1, oradata2, oradata3, oradata4 if possible. This way you take advantage of more than one i/o internally in UNIX (volume/filesystem/file i/o streams).
3. I assume you are talking about LVM striping. There are conflicting vies on this one. It could go either way, sometimes LVM striping helps sometimes it makes i/o slower. It depends on the backend ldev/lun/volume structure. You may want to consider some testing with and without striping.
Sivakumar MJ._1
Respected Contributor

Re: XP24000 and decision on luns size and mutipathing software

Use

50GB to mount on oraexe -->
14.6GB x 4 (RAID5 Distribut the LDEVs from Various RG)

300GB to mount on oradata1
50GB x 6 (RAID5 Distribute the Ldevs form Various RG)

150GB to mount on orasave1
50GB x 3 (RAID5 Distribute the Ldevs form Various RG)

PVLINK is suffecient to take up but the recommendation is to have any multipathing software.

For Redo and Archive logs you can take up 2D+2D or 4D+4D


Mix the Raid groups based on the best combination(146 GB 15K rpm HDD and 300 GB 10K rpm) whichever you have in u r DKUs.
For HP Online Case Logging-->http://support.openview.hp.com/