EVA/CV/SSSU: Reduce Diskcount in Diskgroup

[Herr Ing. RUEHRNESSEL]

Hello,

my objective is to replace an 80x 146GB Diskgroup by an 48x 600GB Diskgroup without Host Downtime. I accomplished this so far by ungrouping each single 146GB Disk according to its RSS ID and RSS Index. I managed to swap 16 Disks a day and let Leveling complete throughout the night. Now I am done with the addition of 48 new Disks and look forward to reduce the Diskgroup by 32 old 146GB Disks. But how can i make sure that during the Ungroup-Phase of each single disk my existing 600GB RS-Sets will not be mixed and merged with 146GB Disks? I'm looking for an SSSU command that can UNGROUP a complete RS-Set or at least specify Disks in multiples of 8? I have not yet found any white paper or best practice document regarding my problem. Have anybody of you got some ideas on this?

Regards
Manfred

[Johan Guldmyr]

Hi, the only SSSU commands are in "HP StorageWorks Storage System Scripting Utility Reference":

http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual〈=en&cc=us&docIndexId=179111&taskId=101&prodTypeId=12169&prodSeriesId=471497

Have you seen this advisory, maybe that can tell you what you need?

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c01888544

A question for me:
When you group the disks by RSS - does that give you all the available space on the disks? And the other way around: if the disk sizes are mixed in an RSS - does that limit the usable space on each disk?

I always thought this was done per disk group and not per rss.

[Uwe Zessin]

The EVA does not allow that type of micro-management. Good luck!

[Herr Ing. RUEHRNESSEL]

Thank you. I managed to get rid of 32 old 146GB Disks by ungrouping the disks according to their RSS ID. Each 146GB-Disk RS Set was first reduced to 6 members. With the next ungroup operation 2 RSS Sets merged to one RS Set containing 11 Members and so on. I kicked out the remaining 11 disks via SSSU script (set disk_group NAME delete=DISK) and now Leveling does the rest without performance impact => Mission completed.

The output of sssu command "ls disk full xml" and Microsofts Logparser Utiliy helped me a lot to query rssid und rssindex information.

Logparser Command to query Disk Information:
logparser -rtp:-1 -fmode Tree "select distinct diskname, modelnumber, firmwareversion, shelfnumber, diskbaynumber, rssid, rssindex from lsdiskfull.xml where (diskgroupname='yourdiskgroup') order by rssid, rssindex"

@Johan: No, usable space is not limited to the smallest disk if you mix sizes. All available space can be used. At the beginning of the merge operation the double amount of the largest Disk Size will be reserved if you use "Single Protection".

@Uwe: Though its not allowed, EVAs can be tweaked :-)

Regards
Manfred

[Herr Ing. RUEHRNESSEL]

...see above