MSA Storage

MSA 2050 SAN – multiple spare disk assignment (pool A/B)

 
M_Kunert
Occasional Contributor

MSA 2050 SAN – multiple spare disk assignment (pool A/B)

Hello Community,
I am missing the option to “assign dedicated spare disk”.

We use 3 enclosure MSA 2050 SAN – each enclosure is split into Pool A/B and each enclosure is hosting one RAID-6 in each pool (left/right side).

We did some redundance/performance tests and removed 2 disks out of each RAID-6 on the last enclosure.
Performance and handling were fine.

But how can we bring back the removed disks?
Ok, I learned already – “dynamic spare” is bad for my case because it assigned spares around all enclosure and pools ☹ - It is disabled now.
Not much better is the “only” set global spare option for my case …
It also makes it 50/50 to bring back all disk into the correct position/enclosure/pool ☹

So, if I have 4 missing disks (2 in Pool A, 2 in Pool B) how can I avoid the random assignment – how is the next, even if I make disk by disk to a “global spare”?

| LUN 1 - Pool A | LUN 1 - Pool A | LUN 2 - Pool B | LUN 2 - Pool B |
| LUN 1 - Pool A | LUN 1 - Pool A | LUN 2 - Pool B | LUN 2 - Pool B |
| LUN 1 - Pool A | LUN 1 - Pool A | LUN 2 - Pool B | LUN 2 - Pool B |

| LUN 3 - Pool A | LUN 3 - Pool A | LUN 4 - Pool B | LUN 4 - Pool B |
| LUN 3 - Pool A | LUN 3 - Pool A | LUN 4 - Pool B | LUN 4 - Pool B |
| LUN 3 - Pool A | LUN 3 - Pool A | LUN 4 - Pool B | LUN 4 - Pool B |

| LUN 5 - Pool A | LUN 5 - Pool A | LUN 5 - Pool A | LUN 6 - Pool B |
| LUN 6 - Pool B | LUN 5 - Pool A | LUN 6 - Pool B | LUN 6 - Pool B |
| _____MDL______ | LUN 5 - Pool A | LUN 6 - Pool B | _____MDL______ |

Best Regards,

Mathias

1 REPLY 1
PrashantS
HPE Pro

Re: MSA 2050 SAN – multiple spare disk assignment (pool A/B)

Hi,

That option to dedicate is no more available. 

Removed command          Replacement command
add global-spare                add spares
add vdisk-spare                  add spares

A controller automatically reconstructs a fault-tolerant disk group (RAID 1, 5, 6, 10) when one or more of its disks fails and a compatible spare disk is available. A disk is compatible if it has enough capacity to replace the failed disk and is the same type (enterprise SAS, for example). It is not advisable to mix 10k and 15k disks in a single disk group. If the disks in the system are FDE-capable and the system is secure, spares must also be FDE-capable.

When a disk fails, the system looks for a global spare. If it does not find a compatible global spare and the dynamic spares option is enabled, it takes any available compatible disk. If no compatible disk is available, reconstruction cannot start.

I know not much of help here. since we cant have dedicated spare option. 

Thanks,

Prashant S. 


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