Raid 5 expansion

[RedBill]

Hey all,

I'm currently running a raid 5 array consisting of 6 1TB drives on an Adaptec 3805 controller and, am looking at adding another two drives to the array as I am running out of space

Based on the amount of time it took to expand last time I added drives to the array (around a month) I'd like to look at what options I have for minimizing time this will take and thus reducing the chance of something going wrong as once started any crash or restart will render the array unusable.

I've outlined the options I can come up with below (none of which are great) and am well and truly open to other suggestions.

--Full Back and rebuild--
Backing up the 4.1TB of data I currently have stored on the array isn't really an option as I don't know any one with that much free space.

I've had a bit of a hunt around for companies that would rent storage in Australia and the best I could find was a tape drive rental service which I suspect doesn't come with tapes.

--Take the array offline then expand--
I suspect that this isn't an option but if some one knows how to do this please let me know.

--Hope--
Start the expansion reduce disk access to the raid as much as possible and hope.

If any one has some tips on speeding this process up it would be most welcome.



Any suggestions or advise would be appreciated.

 

[mikeblas]

I haven't used that specific card; does it not have options for setting the priority of rebuild or expansion operations?

 

[RedBill]

It does, but the month long rebuild I did when moving from 4 to 6 drives was with the priority set to high.

 

[mikeblas]

Wow. Might be time for a new card.

 

[Drudenhaus]

It'd likely be much faster if you expanded by one drive at a time.

 

[RedBill]

Hey Volkum,

Do you have any data on how much faster?

 

[Drudenhaus]

Hey Volkum,

Do you have any data on how much faster?

Data? Like a case study? No.