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Convert RAID 1 to RAID 5

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Occasional Visitor

Convert RAID 1 to RAID 5



Is it possible to convert RAID 1 to RAID 5 without loosing data,OS, and partition on RAID 1 drives while converting to RAID 5?


Server: DL360 G5

Current config: 2 x 146 HD RAID 1 with 2 partition


Additional Drives: 4 x 146 drives


Dennis Handly
Acclaimed Contributor

Re: Convert RAID 1 to RAID 5

It would probably depend on your controller and whether it had write cache or not.

Occasional Visitor

Re: Convert RAID 1 to RAID 5

Thanks Dennis. My Controller is Smart Array P400i and it has Array Accelerator (Cache) Ratio 25% Read/ 75% write. Does it mean its good to go?
Valued Contributor

Re: Convert RAID 1 to RAID 5

I have not seen any HP RAID controller that supports that kind of conversion. Splitting RAID1 to RAID0 is possible and also to expand an existing RAID with some more drives...

But a conversion from 1 to 5 ? I think you will have to backup your data, destroy the RAID1 and create a new RAID5.



"If it seems illogical... you just don't have enough information"
Honored Contributor

Re: Convert RAID 1 to RAID 5

According to the P400i QuickSpecs page, this controller does support Online RAID Level Migration:


Assuming your four extra drives are not a part of an existing array and your BBWC is active, this should work.


From ACU, select your existing array and select Expand Array.  Add the new drives.  You should then be able to choose Migrate RAID/Stripe Size after selecting the Logical Volume.


Note that the migration does take some time and during this process write caching will be disabled.


Have fun!



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Respected Contributor

Re: Convert RAID 1 to RAID 5

I have done this exact thing on a DL360 G5 and it works fine. As other replies noted, you have to make sure your array controller cache has a good battery.

If the battery says it's bad (and that happens a lot on these older servers), it disables the write cache and it also disables other features like online expansion.

All you need to do is insert the new drives and then add all of them to the existing array. Once that's done you can do an online raid level migration with expansion.

It can take a while to do online migration/expansion, so be prepared for a few hours between when you start and when it's all done.

You can adjust the priority of the migration and expansion tasks in the advanced settings of the SSA utility but making it run at higher priority will affect the running system's I/O speed. If it's important to keep your apps running smoothly, leave it set at low priority and just let it take as long as it needs for each step.
Occasional Visitor

Re: Convert RAID 1 to RAID 5

Thank you so much guys for the quick responses. I have tried it and it worked perfectly.


Thank you all

New Member

Re: Convert RAID 1 to RAID 5

Is such a migration possible for the hp proliant dl380 g9 server on the p440ar controller ?? without data loss, this operation will happen? thanks in advance for the answer