optimum disks per controllers

[Chris Baugh]

Client has had an HP consultant on site to investigate their machine set-up. From his findings he reported that there were too many disks on too few controllers, and that there were unused controllers.

A few questions....

1. Is there an optimum no. of disks per controller?

2. Is there any way of identifying the unused controllers, without root access

3. Is there a disk naming convention. THe disks are named like c35t2d5. I've been told that the c35 relates to controller 35, is this the case, and what do the others relate to?

[David de Beer]

I will try to address some of your concerns:

> 1. Is there an optimum no. of disks per controller?

No, I don't believe that you will find anyone that can answer this question without getting more detail on your setup.

The optimum no. of disks per controller depends on how much data you are pushing across the Fibre, how you have setup your machine's ALT paths, how you have arranged your storage on the back-end etcetera. I guess the best answer to your question would be: a setup that allows you to make maximum use of the bandwidth that your controller(s) gives you.

> 2. Is there any way of identifying the unused controllers, without root access

I don't believe so - the easiest way to determine what controllers are being used is using ioscan, which isn't usable by non UID 0 users.

> 3. Is there a disk naming convention.

The CTD numbers are partly generated by the switch, and by the engineer that sets up your XP - if I understand correctly. Your SAN engineer will be able to explain it better.

C35 does not relate to controller 35. You can have c36,c37,cXX drives zoned to a single controller. You can have the same drive zoned to two different controllers on the same machine (So you can use the ALT path). Using the ALT path of a disk will allow you to do some 'home-grown' performance tuning. By either using the ALT path or the first path to a disk in the VG, you can say which way you want traffic to flow to/from your disk. Perhaps this is the problem you experience now, maybe your sysadmin has added all the disks to the VG through the first path.

When we create VG's, we always use the first path, then the ALT, then the ALT, then the first path. This way you can use both controllers, and the second won't just sit there and do nothing. Can you post us the 'vgdisplay -v' of your volume groups? This can be done by a non UID 0 user. Do a ll /dev/vg*/group and post us the vgdisplay -v of the volume groups that you find.

Regards,
David.

[Chris Baugh]

Thanks for the reply, an apologies in advance for the vgdisplay results, below.

--- Volume groups ---
VG Name /dev/vg00
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 20
Open LV 20
Max PV 16
Cur PV 2
Act PV 2
Max PE per PV 4350
VGDA 4
PE Size (Mbytes) 8
Total PE 8680
Alloc PE 7436
Free PE 1244
Total PVG 2
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vg00/lvol1
LV Status available/syncd
LV Size (Mbytes) 152
Current LE 19
Allocated PE 38
Used PV 2

LV Name /dev/vg00/lvol2
LV Status available/syncd
LV Size (Mbytes) 4096
Current LE 512
Allocated PE 1024
Used PV 2

LV Name /dev/vg00/lvol3
LV Status available/syncd
LV Size (Mbytes) 256
Current LE 32
Allocated PE 64
Used PV 2

LV Name /dev/vg00/lvol4
LV Status available/syncd
LV Size (Mbytes) 152
Current LE 19
Allocated PE 38
Used PV 2

LV Name /dev/vg00/lvol5
LV Status available/syncd
LV Size (Mbytes) 2000
Current LE 250
Allocated PE 500
Used PV 2

LV Name /dev/vg00/lvol6
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 128
Allocated PE 256
Used PV 2

LV Name /dev/vg00/lvol7
LV Status available/syncd
LV Size (Mbytes) 2048
Current LE 256
Allocated PE 512
Used PV 2

LV Name /dev/vg00/lvol8
LV Status available/syncd
LV Size (Mbytes) 2800
Current LE 350
Allocated PE 700
Used PV 2

LV Name /dev/vg00/lvol9
LV Status available/syncd
LV Size (Mbytes) 256
Current LE 32
Allocated PE 64
Used PV 2

LV Name /dev/vg00/lvol10
LV Status available/syncd
LV Size (Mbytes) 256
Current LE 32
Allocated PE 64
Used PV 2

LV Name /dev/vg00/lvol11
LV Status available/syncd
LV Size (Mbytes) 400
Current LE 50
Allocated PE 100
Used PV 2

LV Name /dev/vg00/lvol12
LV Status available/syncd
LV Size (Mbytes) 104
Current LE 13
Allocated PE 26
Used PV 2

LV Name /dev/vg00/lvol13
LV Status available/syncd
LV Size (Mbytes) 2000
Current LE 250
Allocated PE 500
Used PV 2

LV Name /dev/vg00/lvol14
LV Status available/syncd
LV Size (Mbytes) 256
Current LE 32
Allocated PE 64
Used PV 2

LV Name /dev/vg00/lvol15
LV Status available/syncd
LV Size (Mbytes) 4096
Current LE 512
Allocated PE 1024
Used PV 2

LV Name /dev/vg00/lvol16
LV Status available/syncd
LV Size (Mbytes) 4096
Current LE 512
Allocated PE 1024
Used PV 2

LV Name /dev/vg00/lvol17
LV Status available/syncd
LV Size (Mbytes) 4096
Current LE 512
Allocated PE 1024
Used PV 2

LV Name /dev/vg00/openv
LV Status available/syncd
LV Size (Mbytes) 120
Current LE 15
Allocated PE 30
Used PV 2

LV Name /dev/vg00/lvol19
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 128
Allocated PE 256
Used PV 2

LV Name /dev/vg00/lvol20
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 128
Allocated PE 128
Used PV 1


--- Physical volumes ---
PV Name /dev/dsk/c0t0d0
PV Status available
Total PE 4340
Free PE 558
Autoswitch On

PV Name /dev/dsk/c1t0d0
PV Status available
Total PE 4340
Free PE 686
Autoswitch On


--- Physical volume groups ---
PVG Name PVG0
PV Name /dev/dsk/c0t0d0

PVG Name PVG1
PV Name /dev/dsk/c1t0d0


VG Name /dev/vgsc10
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 18
Open LV 18
Max PV 16
Cur PV 8
Act PV 8
Max PE per PV 17501
VGDA 16
PE Size (Mbytes) 4
Total PE 139992
Alloc PE 100670
Free PE 39322
Total PVG 2
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgsc10/u01
LV Status available/syncd
LV Size (Mbytes) 8
Current LE 2
Allocated PE 2
Used PV 1

LV Name /dev/vgsc10/u02
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u03
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u04
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u05
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u06
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u07
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u08
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u09
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u10
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/u11
LV Status available/syncd
LV Size (Mbytes) 12
Current LE 3
Allocated PE 3
Used PV 1

LV Name /dev/vgsc10/mdb
LV Status available/syncd
LV Size (Mbytes) 100
Current LE 25
Allocated PE 25
Used PV 1

LV Name /dev/vgsc10/tux
LV Status available/syncd
LV Size (Mbytes) 200
Current LE 50
Allocated PE 50
Used PV 1

LV Name /dev/vgsc10/mdbprcode
LV Status available/syncd
LV Size (Mbytes) 100
Current LE 25
Allocated PE 25
Used PV 1

LV Name /dev/vgsc10/mdbprv
LV Status available/syncd
LV Size (Mbytes) 100
Current LE 25
Allocated PE 25
Used PV 1

LV Name /dev/vgsc10/mdbmig
LV Status available/syncd
LV Size (Mbytes) 200000
Current LE 50000
Allocated PE 100000
Used PV 6

LV Name /dev/vgsc10/mdbprlog
LV Status available/syncd
LV Size (Mbytes) 4
Current LE 1
Allocated PE 1
Used PV 1

LV Name /dev/vgsc10/drtestdata
LV Status available/syncd
LV Size (Mbytes) 2048
Current LE 512
Allocated PE 512
Used PV 1


--- Physical volumes ---
PV Name /dev/dsk/c0t1d0
PV Status available
Total PE 17499
Free PE 0
Autoswitch On

PV Name /dev/dsk/c0t2d0
PV Status available
Total PE 17499
Free PE 0
Autoswitch On

PV Name /dev/dsk/c0t3d0
PV Status available
Total PE 17499
Free PE 0
Autoswitch On

PV Name /dev/dsk/c1t1d0
PV Status available
Total PE 17499
Free PE 0
Autoswitch On

PV Name /dev/dsk/c1t2d0
PV Status available
Total PE 17499
Free PE 0
Autoswitch On

PV Name /dev/dsk/c1t3d0
PV Status available
Total PE 17499
Free PE 4324
Autoswitch On

PV Name /dev/dsk/c0t13d0
PV Status available
Total PE 17499
Free PE 17499
Autoswitch On

PV Name /dev/dsk/c1t13d0
PV Status available
Total PE 17499
Free PE 17499
Autoswitch On


--- Physical volume groups ---
PVG Name PVG0
PV Name /dev/dsk/c0t1d0
PV Name /dev/dsk/c0t2d0
PV Name /dev/dsk/c0t3d0
PV Name /dev/dsk/c0t13d0

PVG Name PVG1
PV Name /dev/dsk/c1t1d0
PV Name /dev/dsk/c1t2d0
PV Name /dev/dsk/c1t3d0
PV Name /dev/dsk/c1t13d0


VG Name /dev/vgmdb_n
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 10
Open LV 10
Max PV 16
Cur PV 12
Act PV 12
Max PE per PV 3473
VGDA 24
PE Size (Mbytes) 4
Total PE 41664
Alloc PE 36661
Free PE 5003
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgmdb_n/u01
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2

LV Name /dev/vgmdb_n/tux
LV Status available/syncd
LV Size (Mbytes) 200
Current LE 50
Allocated PE 50
Used PV 1

LV Name /dev/vgmdb_n/mdb
LV Status available/syncd
LV Size (Mbytes) 100
Current LE 25
Allocated PE 25
Used PV 1

LV Name /dev/vgmdb_n/mdbp
LV Status available/syncd
LV Size (Mbytes) 1400
Current LE 350
Allocated PE 350
Used PV 4

LV Name /dev/vgmdb_n/mdbpl
LV Status available/syncd
LV Size (Mbytes) 1000
Current LE 250
Allocated PE 250
Used PV 1

LV Name /dev/vgmdb_n/mdbpc
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 256
Allocated PE 256
Used PV 2

LV Name /dev/vgmdb_n/u12
LV Status available/syncd
LV Size (Mbytes) 51200
Current LE 12800
Allocated PE 12800
Used PV 6

LV Name /dev/vgmdb_n/u19
LV Status available/syncd
LV Size (Mbytes) 40240
Current LE 10060
Allocated PE 10060
Used PV 5

LV Name /dev/vgmdb_n/u20
LV Status available/syncd
LV Size (Mbytes) 40240
Current LE 10060
Allocated PE 10060
Used PV 6

LV Name /dev/vgmdb_n/tuxsvr
LV Status available/syncd
LV Size (Mbytes) 1000
Current LE 250
Allocated PE 250
Used PV 1


--- Physical volumes ---
PV Name /dev/dsk/c35t0d0
PV Name /dev/dsk/c37t0d0 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t0d1
PV Name /dev/dsk/c35t0d1 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t0d2
PV Name /dev/dsk/c37t0d2 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t0d3
PV Name /dev/dsk/c35t0d3 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t0d4
PV Name /dev/dsk/c37t0d4 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t0d5
PV Name /dev/dsk/c35t0d5 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t0d6
PV Name /dev/dsk/c37t0d6 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t0d7
PV Name /dev/dsk/c37t0d7 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t1d1
PV Name /dev/dsk/c35t1d1 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t1d0
PV Name /dev/dsk/c37t1d0 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t1d3
PV Name /dev/dsk/c35t1d3 Alternate Link
PV Status available
Total PE 3472
Free PE 2841
Autoswitch On

PV Name /dev/dsk/c37t1d2
PV Name /dev/dsk/c35t1d2 Alternate Link
PV Status available
Total PE 3472
Free PE 2162
Autoswitch On



VG Name /dev/vgmdbv_n
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 16
Cur PV 3
Act PV 3
Max PE per PV 3473
VGDA 6
PE Size (Mbytes) 4
Total PE 10416
Alloc PE 10416
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgmdbv_n/mdbpv
LV Status available/syncd
LV Size (Mbytes) 41664
Current LE 10416
Allocated PE 10416
Used PV 3


--- Physical volumes ---
PV Name /dev/dsk/c35t5d3
PV Name /dev/dsk/c37t5d3 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t5d4
PV Name /dev/dsk/c35t5d4 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t5d5
PV Name /dev/dsk/c37t5d5 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On



VG Name /dev/vgmdbdb_n
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 10
Open LV 10
Max PV 16
Cur PV 8
Act PV 8
Max PE per PV 3473
VGDA 16
PE Size (Mbytes) 4
Total PE 27776
Alloc PE 25600
Free PE 2176
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgmdbdb_n/u02
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 1

LV Name /dev/vgmdbdb_n/u03
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2

LV Name /dev/vgmdbdb_n/u04
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2

LV Name /dev/vgmdbdb_n/u05
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 1

LV Name /dev/vgmdbdb_n/u06
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2

LV Name /dev/vgmdbdb_n/u07
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2

LV Name /dev/vgmdbdb_n/u08
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2

LV Name /dev/vgmdbdb_n/u09
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 1

LV Name /dev/vgmdbdb_n/u10
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2

LV Name /dev/vgmdbdb_n/u11
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 2


--- Physical volumes ---
PV Name /dev/dsk/c37t1d4
PV Name /dev/dsk/c35t1d4 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t1d5
PV Name /dev/dsk/c37t1d5 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t1d6
PV Name /dev/dsk/c35t1d6 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t1d7
PV Name /dev/dsk/c37t1d7 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t2d2
PV Name /dev/dsk/c35t2d2 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t2d1
PV Name /dev/dsk/c37t2d1 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t2d0
PV Name /dev/dsk/c35t2d0 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t2d3
PV Name /dev/dsk/c37t2d3 Alternate Link
PV Status available
Total PE 3472
Free PE 2176
Autoswitch On



VG Name /dev/vgmdbdb2_n
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 8
Open LV 8
Max PV 16
Cur PV 15
Act PV 15
Max PE per PV 3473
VGDA 30
PE Size (Mbytes) 4
Total PE 52080
Alloc PE 51115
Free PE 965
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgmdbdb2_n/u13
LV Status available/syncd
LV Size (Mbytes) 17000
Current LE 4250
Allocated PE 4250
Used PV 3

LV Name /dev/vgmdbdb2_n/u14
LV Status available/syncd
LV Size (Mbytes) 27240
Current LE 6810
Allocated PE 6810
Used PV 4

LV Name /dev/vgmdbdb2_n/u15
LV Status available/syncd
LV Size (Mbytes) 17240
Current LE 4310
Allocated PE 4310
Used PV 3

LV Name /dev/vgmdbdb2_n/u16
LV Status available/syncd
LV Size (Mbytes) 22240
Current LE 5560
Allocated PE 5560
Used PV 4

LV Name /dev/vgmdbdb2_n/u17
LV Status available/syncd
LV Size (Mbytes) 18320
Current LE 4580
Allocated PE 4580
Used PV 2

LV Name /dev/vgmdbdb2_n/u18
LV Status available/syncd
LV Size (Mbytes) 20500
Current LE 5125
Allocated PE 5125
Used PV 3

LV Name /dev/vgmdbdb2_n/u21
LV Status available/syncd
LV Size (Mbytes) 46080
Current LE 11520
Allocated PE 11520
Used PV 7

LV Name /dev/vgmdbdb2_n/u22
LV Status available/syncd
LV Size (Mbytes) 35840
Current LE 8960
Allocated PE 8960
Used PV 4


--- Physical volumes ---
PV Name /dev/dsk/c37t2d6
PV Name /dev/dsk/c35t2d6 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t2d5
PV Name /dev/dsk/c37t2d5 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t2d4
PV Name /dev/dsk/c35t2d4 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t3d0
PV Name /dev/dsk/c37t3d0 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t3d2
PV Name /dev/dsk/c35t3d2 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t3d1
PV Name /dev/dsk/c37t3d1 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t2d7
PV Name /dev/dsk/c35t2d7 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t3d3
PV Name /dev/dsk/c37t3d3 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t3d5
PV Name /dev/dsk/c35t3d5 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t3d4
PV Name /dev/dsk/c37t3d4 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t3d7
PV Name /dev/dsk/c35t3d7 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t3d6
PV Name /dev/dsk/c35t3d6 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t4d2
PV Name /dev/dsk/c37t4d2 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t4d1
PV Name /dev/dsk/c37t4d1 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t4d0
PV Name /dev/dsk/c35t4d0 Alternate Link
PV Status available
Total PE 3472
Free PE 965
Autoswitch On



VG Name /dev/vgmdbdb3_n
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 2
Open LV 2
Max PV 16
Cur PV 8
Act PV 8
Max PE per PV 3473
VGDA 16
PE Size (Mbytes) 4
Total PE 27776
Alloc PE 27776
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgmdbdb3_n/u23
LV Status available/syncd
LV Size (Mbytes) 55552
Current LE 13888
Allocated PE 13888
Used PV 4

LV Name /dev/vgmdbdb3_n/u24
LV Status available/syncd
LV Size (Mbytes) 55552
Current LE 13888
Allocated PE 13888
Used PV 4


--- Physical volumes ---
PV Name /dev/dsk/c37t4d5
PV Name /dev/dsk/c35t4d5 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t4d6
PV Name /dev/dsk/c37t4d6 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t4d3
PV Name /dev/dsk/c35t4d3 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t5d1
PV Name /dev/dsk/c37t5d1 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t4d4
PV Name /dev/dsk/c35t4d4 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t5d0
PV Name /dev/dsk/c37t5d0 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t5d2
PV Name /dev/dsk/c35t5d2 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t4d7
PV Name /dev/dsk/c37t4d7 Alternate Link
PV Status available
Total PE 3472
Free PE 0
Autoswitch On



VG Name /dev/vgmdb4
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 141
Cur PV 16
Act PV 16
Max PE per PV 3473
VGDA 32
PE Size (Mbytes) 4
Total PE 55536
Alloc PE 55536
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgmdb4/u25
LV Status available/syncd
LV Size (Mbytes) 222144
Current LE 55536
Allocated PE 55536
Used PV 16


--- Physical volumes ---
PV Name /dev/dsk/c35t6d7
PV Name /dev/dsk/c37t6d7 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t7d1
PV Name /dev/dsk/c37t7d1 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t7d3
PV Name /dev/dsk/c37t7d3 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t7d5
PV Name /dev/dsk/c37t7d5 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t6d1
PV Name /dev/dsk/c37t6d1 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t5d7
PV Name /dev/dsk/c37t5d7 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t6d3
PV Name /dev/dsk/c37t6d3 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c35t6d5
PV Name /dev/dsk/c37t6d5 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t5d6
PV Name /dev/dsk/c35t5d6 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t6d0
PV Name /dev/dsk/c35t6d0 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t6d2
PV Name /dev/dsk/c35t6d2 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t6d4
PV Name /dev/dsk/c35t6d4 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t6d6
PV Name /dev/dsk/c35t6d6 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t7d0
PV Name /dev/dsk/c35t7d0 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t7d2
PV Name /dev/dsk/c35t7d2 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

PV Name /dev/dsk/c37t7d4
PV Name /dev/dsk/c35t7d4 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On



VG Name /dev/vgmdb5
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 141
Cur PV 1
Act PV 1
Max PE per PV 3473
VGDA 2
PE Size (Mbytes) 4
Total PE 3471
Alloc PE 3471
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgmdb5/u26
LV Status available/syncd
LV Size (Mbytes) 13884
Current LE 3471
Allocated PE 3471
Used PV 1


--- Physical volumes ---
PV Name /dev/dsk/c35t7d6
PV Name /dev/dsk/c37t7d6 Alternate Link
PV Status available
Total PE 3471
Free PE 0
Autoswitch On

[Torsten.]

I see your "disks" are LUNs on an array.

Please attach an "ioscan -fn".

In fact, you have to measure the performance with tools like glance.

"How many disks per controller" can only be answered for SCSI connections, in this case it is 15.

In case of performance you have to measure and decide to use more controllers and pathes to the array.

[David de Beer]

Hi Chris,

Next time add your files as an attachment :-)

Your disks look pretty evenly spread out, except for VG vgmdb4.

If there are unused Fibre ports on your machine, I suggest you ask the sysadmin to identify these via ioscan and see if indeed they are already attached via Fibre to the SAN. If they are, you can ask the SAN engineer to zone half of your current disks to the new controllers - to spread the load over perhaps 4 controllers, instead of the 2 that it now seems you have.

This will require a vgexport and vgimport.

What we also like to do is create LV's that are identical to our PV size. This way, if we encounter a LV that is being accessed frequently via 1 controller (as it would be, since a LV then relates to a PV which is seen through 1 controller), it is possible to pvmove that LV to another disk that is configured through your VG setup to be seen by another controller.

But this will only help if one controller is more busy than the other you have.

What is this machine used for? Oracle?

Do you have glance installed on the machine? Can you possibly identify the busy controller(s) and LV's via gpm or using iostat identify the busy disks? If there are multiple LV on the busy disks, you can pvmove them to another (less busy) disk in the VG.

Regards,
David.

[Chris Baugh]

Thanks for replies. Yes the machine is used mainly for ORACLE applications. I'm trying to map ORACLE data files to the physical disks. GLance is showing as 100% disk usage constantly, so I was trying to identify the bottleneck, from an ORACLE view point. My unix is a little limited, hence the questions.

Using sar, I've noticed c35t4d1 is heavily hit, so am trying to work out if there is a need to move ORACLE datafiles around to spread the load.

Would the fact that there are 2 controllers have an impact on the performance. If there are available controllers, which apparently there are, would making use of these help performance of the system?

[A. Clay Stephenson]

The 'c' part of the device node name is the controller instance number and it is not assignned by anyone (well, it can be but that's another story). Do an ioscan -fn and with every 'ext_bus' there is an associated SCSI bus and the instance number (the I column) associated with it becomes the 'c' part. It really represents the order in which the host discovered the controller. This means that identically configured machines could have different instance numbers associated with controllers in the same plysical slot on the two machines. This can happen when new devices are added after the OS was initially loaded. The long version of all this is that there is no hard and fast rule about the assignment of these values.

The other thing to be aware of is the Disk Utilization at 100% may not be all that bad. Glance (or any other host-based performance tool) is clueless about arrays. All it can know is that a big bunch of i/o is going through what it sees as one physical disk (nevermind that this disk is an array LUN and may actually be stripped across 10 disks). Dividing this LUN into smaller LUN's may make things appear better but the overall i/o may be no different.

Now, spreading i/o over multiple scsi buses (controllers) never hurts and, in general, the more separate i/o paths to any kind of array the better.