Raid build taking ages (60hours and counting) - PERC H200

Question

I'm building a RAID1 array with two 2TB drives on a PERC H200 controller. It's been going for 60 hours now and is at 43%. Is it normal to take so long?

Solution 1

The H200 controller disables all disk caching built into the drives by default.

If the server has battery backup you can enable basic drive caching on the Logical Volumes without risk.

Goto www.LSI.com (The controller is made by LSI) and download and install MegaRAID Storage Manager.

Highlight the Virtual Raid Volume, right click, properties. Enable Cache and save.

You have to do this on every logical raid volume.

Your performance difference is incredible.

Solution 2

If you're referring to the "initialize" process, and you're watching it run in the foreground this could take a while depending on the speed of the disks, though 60 hours does seem a bit unreasonable: I've initialized 2TB software RAID arrays on SATA drives in substantially less time than that (about 15 hours).

If I recall correctly the initialization will automatically continue in the background, so you can begin using the array while it's initializing - just expect reduced performance since the controller (& disks) will busy building the array.

A time estimate from Dell's tech support monkeys could be interesting/useful -- If you're seeing substantially worse performance than you "should" there may be a problem with your drives, controller or RAID options...

Solution 3

RAID rebuild will take quite a while on an H200 controller. On a 2Tb SATA setup you're much better of using an H700 with 1Gb NV cache. Performance of SATA drives on an H200 will be fairly poor, how much data are you looking to write each day, if you continuously write large amounts of data on that controller you could potentially see high iowaits whereas an H700 would be much more suitable (at a cost of course).

Comments

[rvs]

It depends. Mostly, on workload. Is system idle or it's on heavy usage?

[Mr. Flibble]

It's idle apart from the RAID building job.

[Philip]

Are these HDs supported by Dell? If not, you may be incurring a substantial performance penalty because of poor drive-controller interactions.