DL380 raid 5 to RAID 1+0

[Sambo_1]

I have a DL 380 G4 with BBWC insatlled. The server has 2 x 36GB (raid 1+0) and 3 x 146GB (raid 5) set up. I have a spare 146GB and want to migrate the raid 5 config to raid 1+0 (it will then have a even pair). Is this possible?

Also, do I have to take the server offline as it I would like to keep it online if possible.

[raadek]

Yes, you can migrate online - virtually from any RAID level to any, using ACU (Array Configuration Utility).

Bear in mind, however, that you should backup your stuff beforehand, just in a case things go messy!

Rgds.

[Sambo_1]

I know I won't be migrating the OS partition, only the data one, how does the migration deal with all the data that is constantly being written/read from the original raid 5 drives?

The raid 5 logical drive contain SQL databases (some over 2 GBs) that is held by the ms sql 2000 process. I guess I don't have to shut down the SQl server then (which is good)!


RAID is amazing technology is all that I can say.

[raadek]

In THEORY you will not have to stop SQL service. However in most cases I have seen, on-line RAID level migration produces so large perfomance hit it might affect the response time really badly.

In my opinion it is worth a try, as when you finish the migration you will benefit from RAID1+0, which outperforms massively RAID5 in random writes (e.g. SQL).

However, depending on your environment you might consider another approach: backup => SQL off-line => delete RAID 5 array => create new RAID10 array => restore from backup => SQL on-line again.

It won't be that fancy as on-line migration, but you have to judge what's better: degraded performance for possibly lengthy period of time (few hours?) or no service during (hopefully) shorter off-line migration.

[Sambo_1]

I tried going into the ACU, assign the fourth 146GB drive (as a spare) to the raid 5 configuration and then tried to migrate. But it doesn't come up with the option to migrate to raid 1+0. The only options are raid 0 to raid 5.

Any help would be appreciated.

[raadek]

I do not think you should add the new drive as a hot-spare - it probably restricts you from migrating to RAID10 as the controller thinks there are still only 3 drives available for data stripping.

[Sambo_1]

Tried takin git out as a spare but still the option doesn't come up. Do I have to expand the array and then convert to raid 1+0?


Sam

[Ravindran.K]

Hi Sam,

Did u succeed in migrating from RAID 5 to 1+0 ?

Regs
Ravindran