How to check data writing to drives in a raid array?

[Callum Bennetts]

Hi

I recently bought my first server (HP ML115 + P400 SmartArray) to install at my work. I have 2 raid 1 arrays and want to check that the data is writing to both disks in each array as data integrity it critical.

What's the best way to test the data is writing to both disks? Simulate a failure by pulling out a disk or is there a better way without disconnecting anything?

Thanks for your help.

[TTr · Accepted solution]

Pulling a disk out is the ultimate test but the array will be in a vulnerable (non redundant) and will go through the process of sparing out if you have a hot spare and a disk rebuild.

Another way is to test is to check the physical and logical status of all array components using the ACU/ADU software.

And finally you can write a large file to a disk volume and observe both disks being written to while the file write is taking place.

[Callum Bennetts]

Thanks TTr

I have a couple of quick questions.

(Pulling a disk out is the ultimate test but the array will be in a vulnerable (non redundant) and will go through the process of sparing out if you have a hot spare and a disk rebuild.)

My configuration is 2 raid 1 arrays A and B. A is 2 500GB drives for the OS and progs, B is 2 1TB drives for my data. If I break array A am I correct in saying that B will be unaffected and remain redundant?

(And finally you can write a large file to a disk volume and observe both disks being written to while the file write is taking place.)

I take it you mean observing this by looking at the drive lights?

[TTr]

> If I break array A am I correct in saying that B will be unaffected and remain redundant?

Yes, array B will not be affected.

> I take it you mean observing this by looking at the drive lights?

Yes. When writing to a mirrored pair, the blinking lights are almost in unison. When you read a file however, most raid controllers will only read one of the two disks and will even alternate between reads.

As always when doing work on the array hardware, do it when the server is least used/needed and after you have done a full backup.

[Callum Bennetts]

Thanks for all your help TTr.

[Callum Bennetts]

I also found this for anyone reading this thats interested. HP's official guide to breaking mirrors and rebuilding drives.

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c00378986/c00378986.pdf