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Replace Vault disks to smaller disks
Hi,
I have a CX4-120 with the vault disks being 5 x 15k 300GB FC disks. If I get 5 x 15k 73 GB FC disks can I do the following:
Replace one 300 GB Vault disk with a 73 GB disk. Let any rebuild finish.
Repeat for each disk.
would this work. Would the resulting Raid Group then decrease in size?
If best practices is to not use the Vault disk for general LUNs, then I'd rather have the FLARE OS (etc) running on the smallest possible disks and use the 300 GB disks for our customers.
thanks in advance,
David
RRR
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September 27th, 2010 02:00
In order to do this there may be NO Raid Groups on the first 5 disks. So use LUN migrate to migrate all LUN's from the first 5 disks to other Raid Groups residing on other than the first 5 disks. Make sure there's no Raid Group left on the first 5 disks.
Pull one drive out, put the smaller drive in and let the rebuild end. Check the Event Log on BOTH SP's to see whether the rebuild has ended. When the lights on the drives stop blinking this doesn't mean that the rebuild indeed ended. Check these logs !! It takes about 30 minutes for each disk.
Repeat this for each of the other disks. When Navisphere doesn't display the right size, stop navisphere and open it again. The refresh of Navisphere Manager isn't that good, so if you trigger a refresh by actually restarting the GUI, it works fine.
kenn2347
542 Posts
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September 27th, 2010 05:00
The steps RRR has are good but one thing to consider is the disk size. I cant find the document i a thinking of but if i remember right, the CX3 series required 60G per disk for FLARE and that was for R26. I dont know if CX4 series FLARE R28-R30 required more disk space per disk. You only get 68G formated space on them so be carefull .
Something to think about
RRR
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September 27th, 2010 07:00
A 73GB drive can be used, but almost no space will be left for user raid groups (18.55 GB), but: for use as Vault disks a 73GB drive is suitable.
Jen_LeClair
111 Posts
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September 27th, 2010 10:00
1) Vault Private Space:
The internal system space requirements for the Vault drives is different for various CLARiiON platforms.
CLARiiON Platform
SATA Drives in the Vault area typically require about 4KB additional overhead per drive
2) Vault drive space can be used for moderate host I/O Loads. It is not a best practice to not use the vault drives for user data LUNs although some customers do choose to do this. For more details and the suggested loads for various types of drives used as vault drives see the section on "Vault and PSM Effects" starting on page 37 of the white paper: EMC CLARiiON Performance and Availability Release 29.0 Firmware Update Applied Best Practices.pdf
RRR
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September 28th, 2010 05:00
So on the CX4 leaving something like 18.xGB for a RAID5 Raid Group. So the 73GB drives are quite suitable for use as Vault drives
DanJost
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September 28th, 2010 06:00
I went through this last year - I opted to have EMC do it. Later on we upgraded it from a CX3 to a CX4 and ran into a load of issues as there was some "metadata" written somewhere that said the drives were bigger than they physically were. They were eventually able to complete the upgrade and a comment was made to me about an update to the "upgrade" tool was going to be released based on the issues they had
I might consider asking EMC to do this for you...it was only a 2 hour deal but they're on the hook if something goes wrong. I went with 146GB drives because 1) I had extra ones of those already and 2) if the flare "size" increases in the future, I should have enough space to cover it.
I agree about not having 300GB drives in the vault. Worse than that, mine were 2Gbit drives - but in the end, everything moved and haven't run into any problems aside from the CX3->CX4 conversion - will let you everyone know when they do the flare 30 update if it rears its ugly head again.
Dan
RRR
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September 28th, 2010 06:00
We never go for the 73GB ones as well. First of all the 146's are common goods and the 73 have become hard to find / expensive and everybody needs some extra space to put some ISO files or something, so the 146's are our favorite as well
. It's not that we think that the Flare code will increase on the CX4's, but when you upgrade to CX5 or so in the future, you might run into the issue after all....
jps00
392 Posts
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September 29th, 2010 10:00
I would pay heed to Jen LeClair's table published above.
Your CX4-120 has years of service in it.
Subsequent releases of FLARE are likely to increase the capacity used by FLARE on the Vault Drives. (Very likely!) If you replace the Vault Drives with drives that are too small, you may have a problem upgrading to newer revisions.
kelleg
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October 5th, 2010 07:00
David,
Was your question answered? If so, please remember to mark the question as answered and to award points to the person with the correct answer.
glen