topic Re: RAID level??? in Disk Enclosures

RAID level???

Jonathan Caplette — Thu, 14 Jun 2001 19:43:10 GMT

Hi guys....

here's an easy one for you... I'm running an HPUX 10.20 box with a 12H AutoRaid array module... when I issue the following command: arraydsp -a , in the first lines I get something that is called ARRAYTYPE, is this the RAID level indicator.. if not how could I get it....

I've a doubt, so if you can light me up!!!

regards
Jonathan

Re: RAID level???

Curt Thompson — Thu, 14 Jun 2001 21:50:13 GMT

Hello Jonathan,

Not really. Because its an AutoRaid array, the data is dynamically moving between RAID 0/1 and RAID 5, depending on the amount of free space in the array and how often the data is accessed. Anyway, my 12H says ARRAYTYPE = 3 and I know this array does not support RAID3.

To see how much free space there is, use:

arraydsp -i

and examine the bottom of the listing. However, knowing what RAID level your data is in at any particular moment might not mean very much two seconds later.

Good Luck,
Curt

Re: RAID level???

Bill McNAMARA_1 — Fri, 15 Jun 2001 10:07:29 GMT

Curt is right.
That is why you selected teh autoraid afterall isn't it?
You're not concerned about what raid level your data is in.

If you want to keep performance relatively okay, you should try to keep the array in as much RAID 1/0 as possible. The only way to controll this from an administration point of view is to leave lots of disk space on the autoraid 'unallocated' for data... this 'free space' will then be used for mirroring raid.

Later,
Bill

Re: RAID level???

Bob Inglis — Fri, 15 Jun 2001 11:33:31 GMT

The AutoRaid makes the decision as to the RAID level of your Data Automaticly. The only control you have over this is the amount of unalloacted space. You Must have enough Unallocated space to cover the Write working set or performance will be impacted.

See, Understanding Write Working Set at: http://us-support3.external.hp.com/cki/bin/doc.pl/sid=99e78d2304c6e8ed85/screen=ckiDisplayDocument?docId=200000054888454