Slow parity initialization of RAID-5 array on HP Smart Array P411 controller

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On 29th October 2011, I built a RAID-5 array using 4 x 146.8GB Seagate SAS ST3146855SS drives running at 15k connected to a PowerEdge R515 with HP Smart Array P411 controller running Windows 2008 (so nothing particularly unusual).

I know that parity initialisation of a RAID-5 array can take some time but it's still running after 2.5 weeks which seems a little unusual.

I'd previously built another array on the same controller using 4 x 2TB SATA-2 drives and that did take a while to complete but a) I'm sure it was less than 2.5 weeks, b) that array was ~12 times bigger and c) during initialization, the percentrage slowly increased each day.

At the moment, the status display for this new 2nd array simply says "Parity Initialization Status: In Progress" and it's said that since the start. It's this lack of change on the status that worries me the most – feels like it's not actually doing anything.

Do you think something has gone wrong or am I being unpatient and for some reason, the status not increasing is normal? I kind of expected a much smaller array on faster drives (15k SAS versus 7.5k SATA-2) to build in a few days.

This is our primary SAN running StarWind so my "have a play" options are very limited. This 2nd array is currently in use for one small virtual disk so I could shut the target machine down, move the virtual disk to another drive and try rebuilding.

Best Answer

Well, it's a little odd. I don't see many cases of mixing HP Smart Array controllers and Dell servers. Either way, the parity initialization doesn't begin until I/O is started on the new logical drive. May I ask how you're monitoring this? Via the HP Array Configuration Utility webpage? Perhaps the HP ACU command-line tool? If you have the latter installed, can you provide the output of:

ctrl all show config detail

We'd like to see that output to see if there's a potential issue with one of your disks.

From the HP Smart Array manual:

Background RAID creation 
When you create a RAID 1, RAID 5, or RAID 6 logical drive, the Smart Array controller must build the 
logical drive within the array and initialize the parity before enabling certain advanced performance 
techniques. Parity initialization takes several hours to complete. The time it takes depends on the size of the 
logical drive and the load on the controller. The Smart Array controller creates the logical drive, initializing 
the parity whenever the controller is not busy. While the controller creates the logical drive, you can access 
the storage volume which has full fault tolerance.

Also, check the firmware on the Smart Array P411 controller. Do you have a cache module installed with a battery or flash backup? If not, you'll have other performance problems over time.

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