Time to Expand an Array

[Andrew McLean_2]

I have a 3x72Gb raid 5 array in a ML350G3 which I have added a forth 72Gb drive to. I have set the controller configuration so that the priority on expanding the array is set to high. How long should it take as I started it on Saturday morning and it is now Tuesday and it is still expanding.

[Uwe Zessin · Accepted solution]

Andrew,
I have read something about 15 minutes per GigaByte on an otherwise idle controller.

[Andrew McLean_2]

Thanks for that, given that the disk is hardly idle, I should expect it to take a few more days. I assume that the 15min per Gb is pysical size of the hard disk and not the amount of data currently stored on the disk. Thanks again.

[Uwe Zessin]

Sure, RAID controllers present a list of logical blocks to the host - they don't have an idea of what a filesystem is. Some advanced controllers like the EVA maintain a map of which 'segments' of a virtual disk have data written to and use this knowlege to optimize replication or snapclones, but that does require additional ressources in the system.