Disk Load Balancing

[Jeremy Blough]

I am wondering if there is a way in 11v1 to do load balancing on disks. I not using lvm for this. I have 2 fiber cards, so each lun is presenting 4 paths. Is there a way to load balance them. I have seen that V3 supports it, but equipment will not support it. Thanks in advance.

[Prashanth Waugh]

Hi,

If you are not using any multipathing tool like EMC power path then you have to do it manully
for eg.
I have 16 luns and having 2 switch (switch A nad Switch B) and 2 HBA Card.
then what i will do for 8 disks the primary path will be through switch A
and alternate path for that 8 disks will be through switch B.
Now for remaining 8 disk i will create the primay path through switch B and alternate path
through switch A.

Regards
Prashant

[Jeremy Blough]

I dont have any software to do that. Also only have 1 fiber switch. Is there another way, the way you described would be great though.

[Prashanth Waugh]

Hi Jeremy,

If u have one fiber switch then u can do the load blancing at disk level
1) stripting at lv level
eg: lvcreate -L 10 -i 4 -I 32 -n lvol1 /dev/v01
it will crate the striping across 4 lun
also
2) U can use the distributed pv logic means u can use the different
lun from different raid group to create the vg.


Regards
Prashant

[Sani]

Hi Jeremy ,

1) Striping logical volumes across disks.

2) Use "Secure Path" for load balancing of HBA's.There are multiple load balancing policies available in Secure path ,which you can use as per your configuration.

Regards
Sanil

[Patrice Le Guyader]

hello,

What you can first do is like on Prashant said on first post, spread accross controllers.

Example (part of vgdisplay -v on a volume group):
--- Physical volumes ---
PV Name /dev/dsk/c5t3d6
PV Name /dev/dsk/c7t3d6 Alternate Link
../..
PV Name /dev/dsk/c7t3d5
PV Name /dev/dsk/c5t3d5 Alternate Link
../..
PV Name /dev/dsk/c5t3d4
PV Name /dev/dsk/c7t3d4 Alternate Link
PV Status
../..
PV Name /dev/dsk/c7t3d3
PV Name /dev/dsk/c5t3d3 Alternate Link
PV Status
../..
PV Name /dev/dsk/c5t3d2
PV Name /dev/dsk/c7t3d2 Alternate Link
PV Status

You can do this online by reducing (vgreduce) and extending (vgextend)on one path of both on one disk on two. You'll see that the alternate will become primary.
If you're not sure post a vgscan -v on one volume group and we advise you.

hope this helps
kenavo
Pat.

[sujit kumar singh]

hi

as you are not using the LVM that means that you cannot make a Striped LV across the Disks.


Also the Alternate Path feature of the LVM also called PV Links does not do Load Balancing. THis is only to give Path Redundancy in case a failure of one of the path takes place.


Here then as suggetsed by Sani, I think Depending on the Disk Array that you might be using , you can take the help of A DMP Software like Securepath EVA -for EVA Disk Arrays, Secure Path XP - if using XP Disk Arrays, EMC PowerPath If using EMC Disk Arrays, Alternatively if using Full Blown Licensed VxVM , then DMP of VxVM.


The Native Dyanic Multipathing and Load Balancing that 11iv3 uses is an inbuilt feature of 11iv3 Only.



Regards
sujit

[Jeremy Blough]

As Suit pointed out I am not using LVM. I am attached to a Netapp SAN, so doing stripping will not work using either lv or pv. I don't know if I have the full version of vxvm or not, guess will have to figure out how to find out. May be possible though that Netapp has a software set that will allow me to set this up.

[Jeremy Blough]

Ok, well I have found the answer to my question. Since I don't have the full version of Veritas, I will have to convert it over to lvm and use a piece perl script from the vendor to setup the multi-pathing up for load balancing. Thanks all to helped.

[Jeremy Blough]

Closed due to answer found.