topic Re: RSS on EVA8000 in Disk Enclosures

RSS on EVA8000

Rotek — Wed, 31 Jan 2007 03:41:17 GMT

I have a customer who wishes to simulate a shelf failure by powering it off to verify availability/redundancy in the DG. Looking at the configuration with Navigator I have the following RSS warning:

RSS #6 has 4 drives that have shelves in common.
Disk 044 loc=(10,02); wwid=2000-0014-C3E6-CC8C; alpa=69;
model=BF14658244; fw=HP02; rss=6.9; size=137; state=good; poid=;
Disk 048 loc=(10,03); wwid=2000-0014-C3E6-CC94; alpa=67;
model=BF14658244; fw=HP02; rss=6.0; size=137; state=good; poid=;
Disk 035 loc=(11,02); wwid=2000-0014-C3E6-BD4E; alpa=7c;
model=BF14658244; fw=HP02; rss=6.8; size=137; state=good; poid=;
Disk 001 loc=(11,03); wwid=2002-000C-CA23-E002; alpa=7a;
model=BF1465A693; fw=HP01; rss=6.1; size=137; state=good; poid=;

Disk Group Disk Count Used Level (%) Alarm Level (%) Used (GB)
Capacity (GB) Oper. State RSS State Req. Spares Cur. Spares
---------- ---------- -------------- --------------- ---------
------------- ----------- --------- ----------- -----------
DG1 80 49 95 5212.62
10658.86 good mirrored single single
DG2 16 90 95 1714.59
1912.99 good parity single single
Ungrouped Disks 4

The graphical representation is attached. My question is will the DG and LUN's/Data contuinue to be available should shelf 10 or 11 be powered down? The DG is all VRAID1.

Thanks in advance for any ideas.

Re: RSS on EVA8000

Uwe Zessin — Wed, 31 Jan 2007 04:36:04 GMT

Disk Group DG1 has an RSS state of "mirrored" which means there are no disk pairs in a single disk drive enclosure. It is my understanding that the group can survive a power-down.

Disk Group DG2 has an RSS state of "parity" which means that there all disk drives of all RSSes are distributed over all disk drive enclosure. It is a 'better' state, although it does not help as long as there are no VRAID-5 vdisks.

From your data it looks like your customer has a 2C8D EVA, but RSS:6 has more then 8 disks. This prevents the "parity" state on DG1.

Re: RSS on EVA8000

Rotek — Wed, 31 Jan 2007 05:11:32 GMT

Uwe,

Thanks - that's correct it is an EVA2C8D, do you know why or how RSS:6 has been assigned more then 8 disks? Is there a way to address this so that Parity can be achieved?

Re: RSS on EVA8000

Uwe Zessin — Wed, 31 Jan 2007 05:36:10 GMT

The RSS split/merge code sometimes works less than perfect. As far as I can tell, there is not 'fixup' code in the controller firmware. You _might_ try to get the desired result by ungrouping and regrouping disks, but I would not hold my breath, sorry.