We are building a RAID of 6 x 4TB drives. My understanding of RAID optimization for Oracle is that random, write intensive uses work best on RAID 10. The next big decision that can have a large impact on DB performance is stripe size. Options for our LSI RAID controller range from 64KB to 1MB.
Has anyone found and ideal size for the manner OA utilizes Oracle?
RAID 10 stripe size for Oracle Server
- vogler
- Posts:122
- Joined: Thu Oct 28, 2010 8:32 am
Re: RAID 10 stripe size for Oracle Server
I think it may depend on the oracle block size... default oracle block size is 8192 (bytes) - which is much smaller than your minimum size, unsure if this is good or bad.
You may think about using Oracle ASM! Then Oracle will handle the disks and striping by its own - I assume that would be the best way (from Oracle point of view) - the disks are attached to and handled directly by Oracle, no OS filesystem, no raid in the controller, ...
You may think about using Oracle ASM! Then Oracle will handle the disks and striping by its own - I assume that would be the best way (from Oracle point of view) - the disks are attached to and handled directly by Oracle, no OS filesystem, no raid in the controller, ...
- nmnogueira
- Posts:125
- Joined: Thu May 05, 2011 12:59 pm
Re: RAID 10 stripe size for Oracle Server
I believe you should create an array in RAID10. This will create a virtual disk with 12TB (you will loose half the capacity), which exceeds the maximum size for a MBR (2TB). Now, I think the Oracle ASM only supports MBR (not GPT), so you will end up with a series of 2TB volumes (which is the maximum MBR supports). Then you create the ASM file system using all these volumes, which Oracle will manage automatically.
- drmalony
- Posts:12
- Joined: Mon Nov 24, 2014 2:33 am
Re: RAID 10 stripe size for Oracle Server
We learned through ETM feedback that ASM handles the striping on it's own, so we don't need to worry about stripe size when using ASM. The hardware RAID controller is set at RAID 1 and then ASM turns it into RAID 10.
- nmnogueira
- Posts:125
- Joined: Thu May 05, 2011 12:59 pm
Re: RAID 10 stripe size for Oracle Server
When you configure ASM you can choose the redundancy level you want: High, Normal or External.
If you choose External ASM will not perform any redundancy, relying on an external redundancy mechanism to protect your data (like RAID!).
Notice that ASM will not turn RAID1 into RAID10. RAID1 means stripping, so it is already performing the redundancy feature for you.
If you choose External ASM will not perform any redundancy, relying on an external redundancy mechanism to protect your data (like RAID!).
Notice that ASM will not turn RAID1 into RAID10. RAID1 means stripping, so it is already performing the redundancy feature for you.
- drmalony
- Posts:12
- Joined: Mon Nov 24, 2014 2:33 am
Re: RAID 10 stripe size for Oracle Server
Good info on ASM. I don't plan on becoming an expert on any function of Oracle, but I do need to ensure that the hardware is prepped properly.
FYI:
"RAID 1 consists of an exact copy (or mirror) of a set of data on two or more disks; a classic RAID 1 mirrored pair contains two disks. This configuration offers no parity, striping, or spanning of disk space across multiple disks, since the data is mirrored on all disks belonging to the array, and the array can only be as big as the smallest member disk. "
https://en.wikipedia.org/wiki/Standard_ ... els#RAID_1
FYI:
"RAID 1 consists of an exact copy (or mirror) of a set of data on two or more disks; a classic RAID 1 mirrored pair contains two disks. This configuration offers no parity, striping, or spanning of disk space across multiple disks, since the data is mirrored on all disks belonging to the array, and the array can only be as big as the smallest member disk. "
https://en.wikipedia.org/wiki/Standard_ ... els#RAID_1
- nmnogueira
- Posts:125
- Joined: Thu May 05, 2011 12:59 pm
Re: RAID 10 stripe size for Oracle Server
My mistake, I wanted to say that RAID1 means mirroring, not stripping! You got the idea anyway 
RAID0 - stripping (no redundancy, big increase in performance)
RAID1 - mirroring (with redundancy, small increase in performace)
RAID10 - mirroring+stripping (with redundancy, big increase in performance)
RAID5 - mirroring with parity (with redundancy, not so good write performance)
I have a mnemonic for that: In RAID0, the "0" means the number of files you can recover if there is a disk failure eheheh
Disclaimer:
While I do have some experience with RAID, I only have basic experience with ASM. Fortunately with had an expert from ETM in the office this week to assist in the configuration of Oracle (and ASM), so those questions have arised.
RAID0 - stripping (no redundancy, big increase in performance)
RAID1 - mirroring (with redundancy, small increase in performace)
RAID10 - mirroring+stripping (with redundancy, big increase in performance)
RAID5 - mirroring with parity (with redundancy, not so good write performance)
I have a mnemonic for that: In RAID0, the "0" means the number of files you can recover if there is a disk failure eheheh
Disclaimer:
While I do have some experience with RAID, I only have basic experience with ASM. Fortunately with had an expert from ETM in the office this week to assist in the configuration of Oracle (and ASM), so those questions have arised.