topic Re: lvcreate in Operating System - HP-UX

lvcreate

José Bispo Santos Filho — Wed, 01 Oct 2003 11:57:58 GMT

I'm using a XP512 (2 FC connections), using OPEN-D disks.
My question is: I need to create a VG with
250 GB, using strip (64k). Does any difference creating this VG with one Lvol or
5 Lvols with 50 GB each. This VG will contain a ORACLE 8i database, on HPUX 11i.
Obs.: Sorry, my poor english.

Re: lvcreate

Mark Grant — Wed, 01 Oct 2003 12:03:46 GMT

To me, it always seems better to have more than one logical volume for your database and particularly preferable to keep your archive logs out of the volume group completely and preferably on another machine.

I would personally recommend creating the volume group with the -s 8 option to vgcreate when dealing with these kinds of size.

Re: lvcreate

Alzhy — Wed, 01 Oct 2003 12:06:03 GMT

If you are using 2Gbps FC HBA's -- I would have the XP512 present LUNS that are on different ACP's (array controller pairs) and array groups... Then in LVM, create PV's out of the LUNs and add them to a VG... You may then create a stripe LVOL -- 4 way with your desired striped size...

BTW, I would not build a stripe that involves an odd number of columns (ie. 5 as you're planning...).

Re: lvcreate

Steven E. Protter — Wed, 01 Oct 2003 12:24:17 GMT

You English is good enough.

Your second option probably won't work.

I think the first option is a good way. Your real problem is that Oracle recommends raid 1 mirror copy, not raid 5 for its databases for performance reasons.

You need mirror/ux to do that with lvm.

lvextend -m 1 /dev/vg##/oradata /dev/dsk/c0t0d0

SEP

Re: lvcreate

Alzhy — Wed, 01 Oct 2003 12:31:38 GMT

The XP512 are already protected LUNS and PVLINKS can also come into play as the HDS LUN is can be multipathed... So no need for any mirroring whatsoever on these LUNs (which can be configured on the frame as wither RAID5 or RAID0+1).

I've worked with XP512's (which is really a rebadged Hitachi Data Systems - Lightning 9960) for the past 3.5 years and the greatest performance out of those LUNs is if you build your volumes (LVOL in LVM terms) that are striped accross LUNs that come from different ACP's and prefereably presented on different CHP's and FC-HBA's.....

I will however recommend you use VxVM to manage/carve your Xp512 LUNs and have your LUN manager operator present those LUN's as multi-pathed ones so you can use DMP or if you insist on using PVLINKS to dual path them...