04-09-2014 11:20 AM - edited 04-09-2014 11:21 AM
We have a node with a bad array controller battery and are looking at ways to replace this with the least amount of down time. There are 12 drives, 280GB each setup RAID10. The volumes that will be effected collectively use 105GB configured in RAID10. If we switch them to RAID5 how much additional space will be required on the SAN to accommodate the growth? I looked all over for a conversion chart but had no luck and I suck at math.
04-09-2014 12:07 PM
Please be more specific...model numbers, MG and cluster configuration, etc.
Are these StoreVirtual/P4000 units?
Is this Network RAID or physical RAID you're describing?
04-09-2014 12:34 PM
HP P4500 system with 4 management groups, 4 clusters and 16 nodes using network RAID. One of the nodes has a bad array controller battery. I am thinking I can just convert the volumes effected by the downtime to RAID5, let the data restripe, and carry on but I only have 956GB free on the SAN so I want to make sure its enough to handle the increase if I convert to RAID5.
04-09-2014 12:51 PM
Based on this information, it seems that you have 4 nodes per cluster, and also your LUNs are thin provisioned.
If so, it should be OK to do the conversion for the affected LUNs, as you have enough nodes and capacity for this kind of conversion.
I would convert one LUN at a time though.
I've gotta ask, if you're doing this conversion, are you going to bring down the problematic node?
Or, are you going to allow your new NR5 LUNs to be striped onto this node?
04-22-2014 01:45 AM
Be careful with Network RAID 5 - it is only meant for volumes with archive type characteristics: almost only read I/O's and a very, very low write rate to the volume.
I am also a bit puzzled why you do need to change the Network RAID level? It is for sure not due to the bad controller battery. This can be fixed while the StoreVirtual volumes can stay online (bring the node into maintenance mode and replace the bad controller battery).