Re: Raid 1 vs Raid 10

Tech Tip: Click here to run a free scan for Windows Errors and optimize PC performance

From: Mark Allison (marka_at_no.tinned.meat.mvps.org)
Date: 09/08/04 

Date: Wed, 08 Sep 2004 14:41:59 +0100

RAID 10 should be faster than RAID1. See

RAID1
http://www.acnc.com/04_01_01.html

RAID10
http://www.acnc.com/04_01_10.html

I have done extensive testing on my hardware and also found that RAID5
was better than RAID1 for transaction logs. Bizarre, I know, but the
truth came out in the testing. So *on our hardware* we went with RAID5
for the transaction logs.

The moral of the story is, you need to benchmark different RAID levels
to get an accurate picture. Things don't always turn out as you expect.
If there's no way you can test your hardware before deciding, then RAID1
should be fine for you, but you *may* get a performance boost by using
RAID10 at considerable extra expense. 

--
Mark Allison, SQL Server MVP
http://www.markallison.co.uk
Looking for a SQL Server replication book?
http://www.nwsu.com/0974973602m.html
Peter The Spate wrote:
> Raid 1 is faster than Raid 10. The official stats are
> 
> operations per disk = (reads + writes) / number of disks
> where as Raid 10 is...
> 
> operations per disk = (reads + (2 * writes )) / 2
> 
> However on my system I have Raid 10 for my log files. The 
> reason is that it offers the best combination of speed and 
> fault talerance, however it is not cheap, which is the 
> reason why we have raid 5 for our data files.
> 
> Get the book SQL Server 2000 Administrator Companion, ir 
> covers it in more detail.
> 
> Peter
> 
> "Action speaks louder than words but not nearly as often" 
> Mark Twain 
> 
> 
> 
> 
>>-----Original Message-----
>>Hi,
>>does anyone know where I can get soma stats on RAID 
>>efficiencies for SQL Server. Basically, I am interested 
>>in the difference between RAID 1 and RAID 10 for the 
>>transaction log. I realise that RAID 1 id the 
>>recommendation, but I need some data to convince the 
>>client that it is more appropriate.
>>TIA,
>>Jim
>>.
>>

Relevant Pages

  • Re: Again: LILO 22.5.9 still gives Error: duplicated volume ID
    ... The 2.4 kernels had serious problems with hardware RAID1 support; ... I've not seen SCSI raid before (hardware). ... but also the two underlying disks. ...
    (comp.os.linux.setup)
  • Re: SQL and RAID - best way to set it all up?
    ... The problem with this is that the results vary depending on the hardware ... that it would be better to place logs on a RAID5 array than a RAID1 ... Looking for a SQL Server replication book? ... > as fast a a raid 5, or a raid 0+1, it's still better to have a separate raid ...
    (microsoft.public.sqlserver.server)
  • RE: my first raid disaster on reboot :o( update
    ... including swap are raid1 and they boot and mount fine now. ... Subject: my first raid disaster on reboot:o(update ... > its corrupt superblock or ext2 file system complaints. ...
    (Debian-User)
  • Re: Is RAID worth it?
    ... as RAID0 (there are also two other HDD's for data/storage set as RAID1), then I read a thread from within this newsgroup in which Carey Frisch directed someone to read - Why RAID is a Terrible Idea http://www.pugetsystems.com/articles?&id=29 and that has made me re-think my plans. ... Is RAID really worth? ... Indeed my own experience of a previous PC with RAID1 showed that it was by no means an easy task to restore everything when one HDD did fail after just 4 months. ... The one think that RAID1 'was' in my mind always useful for was data protection so I'm thinking there must be a way whereby I can install all four drives so that only two are visible and the other two are a mirror image set so that at the end of the day, or maybe twice a day, some software would back up the main visible drives to the 'invisible' back-up drives. ...
    (microsoft.public.windows.vista.installation_setup)
  • =?ISO-8859-1?Q?Re=3A_=5Bfixed=5D_re-enabling_RAID1_on_?= =?ISO-8859-1?Q?existing
    ... I have 2 SATA HDs in my machine that were working as RAID1 earlier. ... So I fiddled around in the BIOS, and decided, in my endless wisdom, to change my SATA from IDE to RAID. ... but my drivers for RAID (Intel® Matrix Storage) are totally gone. ... And I am glad my BIOS reports my drives now on SATA controller as RAID. ...
    (microsoft.public.windowsxp.hardware)