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Creating TDATs on specific disks of a diskgroup
I would like to know the feasability of creating tdats on specific disks of a diskgroup.
The diskgroup has 24 disks and in a couple of weeks time 8 disks will be moved to a different disk group, so is it feasible to create TDATS on specific 16 disks only without spreading hypers on remaining 8 disks?
Thanks
bhalilov1
114 Posts
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July 25th, 2014 13:00
Are these 24 disks the only disks from particular speed/size ? If you have other disk groups with the same type of disks, you can ask EMC to join these disks groups and you will end up with much better configuration.
sauravrohilla
859 Posts
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July 24th, 2014 23:00
i dont think u have the option to choose disk when creating the devices in symcli, may be its available in symmwin, where you may choose disks to create hypers..
Roshan_Raju
53 Posts
1
July 25th, 2014 06:00
Agree with Saurabh, via SYMCLI you would not have an option of selecting physical disks on which you can carve out the hypers. Contact your local EMC field team and have this discussed with them. Bin file can be configured to achieve what you are looking for.
Regards,
Roshan Raju.
bhalilov1
114 Posts
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July 25th, 2014 08:00
16 disk group is awfully small, I hope you have a good reason to do this
assuming all 24 disks are completely empty, and you know exactly which disks they will be removing
-create large unprotected volumes to fill all 24 disks to close to 100%
-for each of the 16 disks to remain in the group, run symdisk show and create a list of the unprotected volumes on them
-delete these volumes (they will not be consecutive and you will need multiple lines in your symconfigure commend file).
this will leave your target 16 drives empty and the 8 to be removed full
-create your TDATs - they will be placed on the 16 disks
-to cleanup the 8 drives to be removed, run symdisk show create another list of the unprotected vols and delete them
12122
82 Posts
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July 25th, 2014 12:00
thanks Roshan & Saurabh
12122
82 Posts
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July 25th, 2014 12:00
bhalilov@un
Yes it is a very small diskgroup that will be used for clone devs for a particular application only. To be frank I have no idea which disks will be removed in order to balance the disks at the backend for that diskgroup.
I wanted to check is there any feasability and also to know the total usable capacity of TDATS that can be created out of 16 disks.
Let me try out your method and thanks a lot
Quincy561
1.3K Posts
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July 25th, 2014 12:00
I generally dislike isolating clone targets at all, and dislike it more when the disk group is small. Your copy times could be a lot longer, and if you don't do a copy, the versioned WP that get created when you do a copy-on-write could cause array issues with WP counts.
12122
82 Posts
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July 25th, 2014 12:00
Quincy56,
Sorry it is not clone, it is going to be Symmir (BCV).
12122
82 Posts
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July 25th, 2014 13:00
Hope you meant symmir commands will be translated to clone.
Yes, thats true and that diskgroup is particularly for clone purpose and the data devs will be configured with RAID-5 (3+1).
Quincy561
1.3K Posts
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July 25th, 2014 13:00
VMAX does not and never has supported BCVs, only clones. When you use symclone commands they are translated to clone commands.
Quincy561
1.3K Posts
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July 25th, 2014 13:00
Yup.. :-D symmir -> clone
12122
82 Posts
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July 25th, 2014 14:00
bhalilov@un,
You are absolutely right but here in this environment segregation is high priority than performance. That might be the reason architect has created many small sized disk groups.
Quincy561
1.3K Posts
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July 25th, 2014 15:00
You realize that such segregation can cause a larger impact on the other devices than not segregating the devices.