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TDAT cylinder size best practises
Hi
We just added 116 + 4 spares , SATA 2 TB drives into the new disk group. I am trying to determine the Cyl size and the volume count for this disk group. Below are my current disk group information and basing on the facts I got 13 hypers on a 1TB drive and 8 hypers on 600GB drives irrespective of the type of drive FC/SATA. Would it be fair to carve 26-28 hypers on a 2 TB drives following the analogy ?
Basically my question is to find out the tdat count and size for the new disk group for VMAX 5875 and for RAID 5
DG - 1 , 7.2K & 1TB
Ident Symb Int TID Vendor Type Hypr Total Free Actual
------ ---- --- --- ---------- ---------- ---- ---------- ---------- ----------
DF-1A 01A C 4 SATAHGST C02THJK 13 953870 1 1823565
DG - 2 , 7.2K & 1TB
Ident Symb Int TID Vendor Type Hypr Total Free Actual
------ ---- --- --- ---------- ---------- ---- ---------- ---------- ----------
DF-1A 01A C 0 SATAHGST C02THJK 14 953870 5 1823565
DG-3, 10k RPM & 600FC
Ident Symb Int TID Vendor Type Hypr Total Free Actual
------ ---- --- --- ---------- ---------- ---- ---------- ---------- ----------
DF-1A 01A C 8 SEAGATE ERC6010 9 558281 4 558281
DG-4 , 10k & 600 FC
Ident Symb Int TID Vendor Type Hypr Total Free Actual
------ ---- --- --- ---------- ---------- ---- ---------- ---------- ----------
DF-1A 01A C C SEAGATE ERC6010 8 558281 8 558281
Would appreciate for an answer
karthik_jupudi
6 Posts
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May 8th, 2012 10:00
Thanks for quick response. Yes the client demands for RAID 5 3+1. No I am configuring separate pool.
Quincy561
1.3K Posts
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May 8th, 2012 10:00
A couple of things.
Are you sure you want RAID5 on SATA?
What RAID5? 3+1 or 7+1?
Are you planning on putting those in the same pool with the 1TB drives?
Quincy561
1.3K Posts
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May 8th, 2012 11:00
The most important thing is to have the same number of TDATs on each drive.
From my calculations, a 2TB drive has 1,915,210 cylinders.
So the total usable capacity is that times 3 for 3+1 or 5,745,630
The largest hyper you can create is 262,668, but that won't go in evenly.
So I would create 22 3+1 TDATs on each set of 4 drives size of 261,165 and repeat for a total of 638 TDATs.
karthik_jupudi
6 Posts
0
May 8th, 2012 11:00
Thanks for the concept and all the TDAT no's and cyl sizes match to my existing below DG's (table below) and that is what I am looking for.
There is one quick thing that did not match 2 TB = 1915210 Cyl as basing on below
Cylinders = GB / 15 / 128 / 512 * 1024 * 1024 * 1024
2236962 = 2048/ 15 / 128 / 512 * 1024 * 1024 * 1024 ??? Plz correct me if I missed something
Count
Size (cyl)
Group
Mirror Type
Special Type
280
0
1
NORMAL
POWR
4
8738
1
2-MIR
SFS
1
3
2
2-MIR
ACLX
56
3
2
2-MIR
None (GKs)
612
246897
1
3RAID5
TDAT
612
249083
2
3RAID5
TDAT
912
73288
3
2-MIR
TDAT
616
219870
4
3RAID5
TDAT
616
219870
5
3RAID5
TDAT
624
219870
6
3RAID5
TDAT
624
219870
7
3RAID5
TDAT
karthik_jupudi
6 Posts
0
May 8th, 2012 12:00
You are right . Great and thanks a lot for your help. You made my day
------ ---- --- --- ---------- ---------- ---- ---------- ---------- ----------
DF-2A 02A D 2A SATAST C02TMSP 0 1915210 1913711 1915210
DF-2A 02A D 2C SATAST C02TMSP 0 1915210 1913711 1915210
Quincy561
1.3K Posts
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May 8th, 2012 12:00
I looked at the drive in SymmWin and it had DB2DADD1 blocks.
I know that the 2TB drive is formatted differently than the 1TB drive to gain performance, but some capacity is lost.
You can see the actual cylinder count on your drives with the symdisk list -cyl command.
karthik_jupudi
6 Posts
0
May 8th, 2012 12:00
Will configure and let you know how it goes.
Quincy561
1.3K Posts
0
May 8th, 2012 12:00
Although you may want to use the "free" count. I doubt it will let you use more than is free.
karthik_jupudi
6 Posts
0
May 18th, 2012 12:00
Hi Quincy
This is what my SA recommeded finally and I carved with this measurements
Quincy561
1.3K Posts
1
May 18th, 2012 12:00
The number of TDATs should work out so that every disk has the same number of them.
If not, have the SA do it over, or have them talk to me.