EVA 4400 upgrade - free disk space requirements

[steveshep1]

Hello,

I want to upgrade an EVA 4400 to firmware version XCS 11200000. 

Our disk groups are pretty full - both at 99% allocated, one has 60GB free and the other one has 120GB.

I'm just wondering if anyone knows how much free space is required on the disk groups for the upgrade to succeed.

After our last upgrade the free space in the disk groups shrank - apparently this was because of a change in the way the disk drive failure protection works.

I've been through the docs but I can't see anything to say if this firmware upgrade will do something similar and there is no info on how much space is needed on the disk groups.

Thanks,

Steve

[Cali · Accepted solution]

Hello,

take a look in:

HP StorageWorks 4400 Enterprise Virtual Array configuration best practices white paper

for

Proactive disk management.

Proactive disk management (PDM) is a request by a customer or HP Services to ungroup a disk, or it is a predictive disk failure request by the EVA to ungroup a disk.

In either case, the array migrates the contents of the disk to free space beforeremoving the disk from
use. PDM can occur only if sufficient free space isavailable. PDM operation capacity is independent
of protection level capacity. Customers who desire the highest levels of availability elect to reserve
additional free space for PDM.
The capacity used for PDM is twice the largest diskin the disk group for each PDM event anticipated.
Typical choices are none, one, or two events. The greater the disk count in a disk group, the greater
the opportunity for a PDM event.
Best practice to optimize availability. Set the occupancy alarm to allow space for one or two PDM events per disk group.

Leveling and reconstruction.

Leveling and reconstruction performance can be optimized with a minimum of 5 GB of free space per disk group.
Best practice to optimize availability.

Set the occupancy alarm to the larger of the capacity required for PDM or the total HPContinuous Access EVA write history log capacity, plus 5 GB. This capacity is converted into a percentage of the raw capacity and then rounded to the next largest whole number. The pseudo-Excel formula would be as follows:
Occupancy_Alarm = 100 – ceiling ( ( max 3 ( PDM_capacity, HP Continuous Access_log_sum) + 5GB ) / total_disk-group_raw_capacity ) )

[steveshep1]

Thanks very much for the information.

Steve