Currently i have this 2 disks ( Please see the attachement) and i bought 2 new ones.. if i destro the current configuration and add all the 4 disks will it impact anything ?
It doesn't explain me what will happen if i destroy the current configuration.. it just explains me the best practices.. if i destroy it now and redo it with 4 drives will it affect my fast cache lun's ?
when you select to destroy fast cache, it will need to de-stage everything from it to disk first. During that time you might see higher response times, especially for applications that took advantage of it ..so best to do it during low activity times.
We are not using any storage pool lun's... its all traditional lun's we are using fast cache on.. my boss just asked me what if we disable the fast cahce on all lun's and destroy the fast cache and readd it...
can you please explain the difference between destroying and readding the fast cahce and/or disabling the fast cache on lun's and redoing the fast cache on lun's
Thats really helpful.. I have one last question...
If i go to each lun and disable fast cache will that affect anything ? Whn i disable fast cache does it show me how much time it takes to destage the data ?
for pool LUNs you can't disable it on per LUN bases, you disable it for the whole pool. For traditional raid group LUNs you can disable it on per lun bases. Why do you want to do that ?
I don't remember seeing a progress bar or anything like that whey you are destroying it.
you can disable Fast Cache for traditional LUNs where you know you are not getting any benefits (backups, archive logs). Why would you want to disable Fast Cache for all LUN, destroy/rebuild Fast Cache and then go back and re-enable Fast Cache on all LUNs ? Destroy Fast Cache, rebuild .and you are done.
dynamox
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November 21st, 2012 07:00
page 21
http://www.emc.com/collateral/software/white-papers/h8046-clariion-celerra-unified-fast-cache-wp.pdf
dynamox
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November 21st, 2012 07:00
you will need to destroy fast cache and re-create it with the old and the new drives.
bonnu06
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258 Posts
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November 21st, 2012 07:00
Currently i have this 2 disks ( Please see the attachement) and i bought 2 new ones.. if i destro the current configuration and add all the 4 disks will it impact anything ?
bonnu06
2 Intern
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258 Posts
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November 21st, 2012 08:00
We have VNX5700 and i guess we can have upto 4 * 200GB flash drives.
bonnu06
2 Intern
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258 Posts
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November 21st, 2012 08:00
It doesn't explain me what will happen if i destroy the current configuration.. it just explains me the best practices.. if i destroy it now and redo it with 4 drives will it affect my fast cache lun's ?
dynamox
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20.4K Posts
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November 21st, 2012 08:00
read page 21 , it explains what will happen.
dynamox
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November 21st, 2012 08:00
when you select to destroy fast cache, it will need to de-stage everything from it to disk first. During that time you might see higher response times, especially for applications that took advantage of it ..so best to do it during low activity times.
https://community.emc.com/docs/DOC-11313
bonnu06
2 Intern
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258 Posts
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November 21st, 2012 08:00
We are not using any storage pool lun's... its all traditional lun's we are using fast cache on.. my boss just asked me what if we disable the fast cahce on all lun's and destroy the fast cache and readd it...
can you please explain the difference between destroying and readding the fast cahce and/or disabling the fast cache on lun's and redoing the fast cache on lun's
bonnu06
2 Intern
•
258 Posts
0
November 21st, 2012 08:00
Thats really helpful.. I have one last question...
If i go to each lun and disable fast cache will that affect anything ? Whn i disable fast cache does it show me how much time it takes to destage the data ?
dynamox
9 Legend
•
20.4K Posts
0
November 21st, 2012 08:00
for pool LUNs you can't disable it on per LUN bases, you disable it for the whole pool. For traditional raid group LUNs you can disable it on per lun bases. Why do you want to do that ?
I don't remember seeing a progress bar or anything like that whey you are destroying it.
dynamox
9 Legend
•
20.4K Posts
0
November 21st, 2012 10:00
you can disable Fast Cache for traditional LUNs where you know you are not getting any benefits (backups, archive logs). Why would you want to disable Fast Cache for all LUN, destroy/rebuild Fast Cache and then go back and re-enable Fast Cache on all LUNs ? Destroy Fast Cache, rebuild .and you are done.