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13 Posts
1
2856
May 22nd, 2012 08:00
AX4-5F Vault Drives - Separate LUN?
Hi,
I am ready to set up a newly aquired CLARiiON AX4-5F with 2 ESXi 5.0 servers.
Having read through the following documents...
http://weblogs.asp.net/craigg/archive/2011/02/17/dell-emc-ax4-5-vault-drive-upgrade.aspx
... I'm unsure as to whether I should be setting aside drives for exclusive use as Vault Drives.
Also, if I leave the Vault Drives as part of my operational LUN, what is the impact in regards to size available from the remaining drives?
Perhaps I am being over cautious being a relative newbie to SAN technology.
I would be very intersted to hear opinions please.
Best regards,
Steve
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rupal1
433 Posts
0
May 23rd, 2012 02:00
The Vault drives are the first 4 drives in the AX4-5 (0,1,2,3). You can identify them by the little yellow stickers that warn you not to move the drives from their location. And you shouldn’t. The Vault drives contain OS, config and other information. If you pull these drives from the system, it will not fully boot (you can still connect via serial). If these drives fail in a certain sequence, the same fate will ensue. Simply put, you need them to be healthy.
Should I separate the Vault Drives (1st 4 drives) into their own RAID Array? Yes, EMC does not recommend binding the luns on the vault area.
EMC does not recommend creating a large RG in which you include the vault area drives also as the vault area handles already Boot Partition, Primary boot disk, Secondary boot disk, Utility Partition and many important functions of the OS. So even if there is a slight dip in performance it becomes very tedious to locate the lun/disk suffering from performance dip.
If later you realize that you need some more space then you can use your vault drive and may present it to the app that has low I/O's thats the best recommendation i can give.
Might help
AnkitMehta
1.4K Posts
0
May 22nd, 2012 09:00
It is recommended that you be careful with provisioning RAID groups containing user data on the Vault drives. It is possible for RAID groups created on the Vault drives servicing a production workload to impair overall system's performance, or adversely affect storage system's availability.
Please, refer to Vault Drive section of EMC CLARiiON Best Practices for Performance and Availablity.
(https://community.emc.com/docs/DOC-16058)
Knaphie
13 Posts
0
May 23rd, 2012 01:00
Hi AnkitM,
Thanks for the response, but all you have done is point me at the same document I read (1st link in my original post).
Allthough like you I read page 95, this does not answer my questions which is why I posted here. I have aquired an AX4-5F with 12 x 600GB drives.
To reiterate my question - when initialising and preparing the SAN for use with 2 x ESXi 5.0 servers (vSphere 5.0) ...
Regards,
Steve
rupal1
433 Posts
0
May 23rd, 2012 03:00
Can I assume that these can be set up as a RAID5 set? yes you can go ahead with a Raid 5 set on the vault.
Go ahead with the config on your AX now...you are all set
Knaphie
13 Posts
1
May 23rd, 2012 03:00
Hi Rupal,
Brilliant. Once again many thanks.
Regards,
Steve
Knaphie
13 Posts
0
May 23rd, 2012 03:00
Hi Rupal,
Your answer is almost exactly what I've been looking for. Many thanks.
For info, after checking around the forum, I found in the following document (Page 39)...
http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H2358_clariion_best_prac_fibre_chnl_wp_ldv.pdf
That the CLARiiON uses 33GB per drive for it's OS etc. This answers my sizing question too.
So in my case, I will now buy a set of 4 small drives for use as the Vault drives so that I don't waste too much space. Can I assume that these can be set up as a RAID5 set?
If my assumption is correct, I should then be able to use the "spare" space on the Vault drives for less resource intesive storage as and when required.
Finally, the rest of my 1st bay will now be configured as RAID5 with a global hot spare.
Regards,
Steve