Disk Manager; Mirrored Volume Questions

[zeroxcorbin]

Hello, I have a couple questions about how mirrored volumes are handled by disk manager.

1: When a member of a mirror set is being resynchronized and the computer is rebooted, the re-sync process restarts at zero percent. Is this the intended behavior or do I have drive or controller issue? Re-syncing 2TB drives without being able to restart the server is very frustrating and causes excessive wear to the drives.

2: Is there a way to actively monitor the progress of a mirror re-sync? I realize leaving Disk Manger open will eventually update the status of the rebuild with a percentage. However, this can take hours for a value to be displayed. I would like a way to actively poll the re-sync status. Any ideas?

Win2k8 RC2 x64 SP1
IBM x3800 system

Thank you,

 

[ICTCity]

Hi,

Everything depends on controllers / software used.

Rebuild a 2 tb disk is a huge work, on windows disk manager you can simply update the screen to get the current status.

Usually you can't restart (or you shouldn't) your system, once you do this, the process will restart.

I know that some controllers have 2 options via a GUI on windows: priority and resume. As said only some controllers have these features...

 

[zeroxcorbin]

Thank you for the reply ICTCity,

Maybe I should have been more clear. This is not hardware RAID. This is volume RAID 1 through Disk Manager.

I have found that it is faster to copy the data to a spare drive, break the mirror, create the mirror, and copy the data back. This takes about 10 hours. A re-sync can take five days or more.

As for refreshing Disk Manager, this does not work for me. It actually clears the percentage display.

For example;

If I see "Re-synching(15%)", after a refresh I see "Re-synching". The percentage value only updates every 3% of the re-sync, or at least this is what I have observed. I was hoping there was a command line tool or API to query the current percentage complete.

Anyway, bottom line, a 2TB 3Gb/s re-sync should not take 5+ days when it only took me five hours to copy 1.75TB to the mirror.

If Microsoft is listening, it would be nice to have a way to pause the re-sync if a reboot is required. It would also be nice to have a continuous update of the percentage complete.

Thanks,

 

[ICTCity]

Thank you for the reply ICTCity,

Maybe I should have been more clear. This is not hardware RAID. This is volume RAID 1 through Disk Manager.

I have found that it is faster to copy the data to a spare drive, break the mirror, create the mirror, and copy the data back. This takes about 10 hours. A re-sync can take five days or more.

As for refreshing Disk Manager, this does not work for me. It actually clears the percentage display.

For example;

If I see "Re-synching(15%)", after a refresh I see "Re-synching". The percentage value only updates every 3% of the re-sync, or at least this is what I have observed. I was hoping there was a command line tool or API to query the current percentage complete.

Anyway, bottom line, a 2TB 3Gb/s re-sync should not take 5+ days when it only took me five hours to copy 1.75TB to the mirror.

If Microsoft is listening, it would be nice to have a way to pause the re-sync if a reboot is required. It would also be nice to have a continuous update of the percentage complete.

Thanks,

In a productional environment, you never do a software based raid, instead you have a dedicated controller. Also, usually you don't use 2 tb for each disks because of perfomances are really poor.

If you right click DISK MANAGEMENT and then click on REFRESH you have the same result?!

Microsoft cannot add a "pause" button because of the thing is managed by SOFTWARE. So, once the OS is turned off, the raid cannot be monitored anymore.

3GB/s doesn't mean anything... remember that your BUILT-IN RAID is managed by the same chipset, so your 3 GB/s must be divided by normal disk usage, raid rebuild. In a normal condition (2 SEPARATE DISKS), try to copy 1 GB file from disk A to B, your speed will never be 3 GB/s, instead 20-30 MB/s right? Right!

So, if you want more performances, switch to a dedicated RAID CONTROLLER (a good one costs about 200$).