convert Raid5 to Raid 1+0 on HP E200

[Mario Gaucher]

Hi,

I have a HP E200 controller with the 128MB cache in my ML150 G3 server.

I have two raid volume...
- 1 x Raid 1 with two drives
- 1 x Raid 5 with three drives

there is one drive left as a spare for both raid volumes. All drives are identical...

is it possible to convert the raid 5 volume to raid 1+0 (using 4 drives)?

Right now, the HP ACU only allows me to convert to Raid0... but if I do this, will I be able to convert to Raid 1+0 after that?

[gregersenj]

You can convert from a RAID 5 to a RAID 1+0.

add the 4th disk to the array (Expand) then migrate to 1+0.

First you have to remove the spare from both arrays.

BR
/jag

[Mario Gaucher]

thanks for your help...

how much time could it take to expand my raid5 (currently with 3x250Gb sata drives) to 4 drives?

Will it slow down normal operations on the server?

[gregersenj]

Hi Sorry,

I have been busy.

I don't know how long it will take.
But HP say rebuild can take up 15 min/GB. In worst case.

I believe it could take 1 - 2 days.

Unless you have a very high load on you disk system, you shouldn't see a performance impact.

I would do it in a weekend anyway.

ps.
You might need to buy a Cache battery for the e200 to be able to do a RAID level migration.

[Mario Gaucher]

thanks for your help...

the current volume is 3x250Go Raid 5...

so if it really takes 15mins/GB, it could take in my case more than 115 hours...

I really hope it will be a lot less than that.
Or is it 15mins/GB for real data and not complete volume? If it's the case, I have 160GB worth of data... it will be faster if the raid controller only needs to "work" where there is some data.


I have a 128MB cache on my E200... so I should be ok.

[gregersenj]

It's an on-line opration. So you will still be in production.

15 min/GB is worst case.

So, these modern large drives do have a downside.

regarding the cache. You might have to buy a cache battery, to enable the migration option.
It is being mention often, on itrc forum, that the e and P model smart array controlers need a to enable write cache to perform a RAID level migration.
And to enable write cache, you need a battery, also known as BBWC (Battery Backed Write Cache).

BR.
/jag