AutoRAID Configuration

[Jack Fan]

I have one AutoRAID 12H and 18G * 8 HDs, I want to re-create disk array for ORACLE db use. Which architecture is good for database (OLTP)?
1. create 8 LUNs onto 8 disks then create 1 VG onto 8 LUNs, and create 2 or 3 LV used to data file and index file and redo file or archive log file.

2. Create 8 LUNs onto 8 disks then create 2 VGs onto 4 of 8 LUNS and create LV for each VG.

Thank In Advance

Jack Fan

[Steven Sim Kok Leong]

Hi,

I think whether you use 1 VG or 2 VGs has minimal performance impact.

From the OS perspective, you cannot stripe or mirror across disks from one VG to another VG. If you use only 1 VG, you can have to option to stripe and/or mirror across more disks and across more controllers.

From the OS perspective, if you stick to only 1 VG, you cannot have the flexibility of defining different RAID configurations for different VGs.

The RAID level you use in your AutoRAID will have an impact on performance and availability.

For OLTP, are you using RAID 0+1 ie. RAID 0 for performance and RAID 1 for full redundancy or RAID 5?

One thing to note about redo logs and archive logs is that they are sequentially written into. Thus, they should not use striped volumes, unlike data and index which are randomly-accessed.

Hope this helps. Regards.

Steven Sim Kok Leong

[Patrick Wallek]

For maximum performance, you will want to define only about 50-60% of your capacity for LUNs on your autoraid. This will allow the 12H to automagically keep data in RAID 0/1 configuration and force it all into RAID5. You have no choice, other than your LUN configuration, as to how the AUTORAID moves data between RAID 5 and RAID 0/1.

When defining your LUNs on the AUTORAID, you are NOT defining a single LUN to a single disk. The data is automatically striped across all disks in the AUTORAID.

Check out this thread for more information on configuring the AutoRaid for Oracle.
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x244fded2442ed5118fef0090279cd0f9,00.html

[Mark van Hassel]

Hi,

Also, do not configure 8 LUNS ! * luns is the maximum for an autoraid. This means that you can not add more LUNs inm the future. For best performance it is best to create about 5 LUNs.

When there are two controllers installed in the autoraid, you should load balance over the two controllers.

HtH,

Mark.