Dynamic Load Balancing Drivers Wanted

[Laurie A. Krumrey]

Hi All,

I have my HP boxes (11.0 and 11i models L2000, N4000, K360) connected to EMC disks.

We have two channels we are using for each HP server. One primary path and one alternate path for each EMC disk device.

Are there any Load Balancing Drivers for managing which channel to use? We want automatic fail over also.

All our Fiber Cards are the lastest and greatest A5158A. We have the lastest patches and firmware, we just need the Load Balancing Driver(s). Our topology is fabric (only the best).

I know EMC makes one called Power Point for about $5,000, we would really rather have an HP driver.

Anyone know?
Laurie

[linuxfan · Accepted solution]

Hi Laurie,

I haven't used any load balancing drivers, but in the past what i have done is configure my LVs so that one uses primary path , the second LV uses the alternate path as primary and so on and so forth.

Eg:
Lets say your primary disks are /dev/dsk/c4t1d0 /dev/dsk/c4t1d1 on your primary path, and /dev/dsk/c5t1d0 and /dev/dsk/c5t1d1 on your secondary path, configure your Lvol1 so that it uses /dev/dsk/c4t1d0 and extend it to /dev/dsk/c5t1d0 and lvol2 uses /dev/dsk/c5t1d1 as primary and extended to /dev/dsk/c4t1d1

This way you are load balancing without any additional drivers.

Just a thought

-Regards
Ramesh

[Victor BERRIDGE]

Hi,
Im not sure HP has such a driver, all I can think of at the moment other than EMS'c product is VERITAS volume manager which does also dynamic load balancing...


All the best

Victor

[James R. Ferguson]

Hi Laurie:

You are thinking of EMC's "PowerPath", not that other OS product "PowerPoint".

As for load-balancing, LVM does not load-balance between alternate (pv) paths. An alternate path to LVM is only for failover should the primary path fail.

If you wanted to move to VxVM, dynamic load-balnacing *is* a part of that product. For more information on VxVm, begin here:

http://docs.hp.com/hpux/onlinedocs/B7961-90021/B7961-90021.html

Regards!

...JRF...

[A. Clay Stephenson]

Hi Laurie:

You already have it. It's called LVM.

Let's suppose that you need a new volume group, vg10, that needs to be 200GB. You dont create 1 LUN for this, you create 2 100GB LUNS.
The primary path for LUN1 we will call /dev/dsk/c3t4d1 (secondary /dev/dsk/c4t5d1) and the primary for the 2nd, LUN2, we will call /dev/dsk/c4t5d2
(secondary /dev/dsk/c3t4d2) - note that the primary controllers (and thus the fiber channels are flipped between them).

Now lets create a Vg in the usual way:

cd /dev
mkdir /dev/vg10
chmod 755 /dev/vg10
cd vg10
mknod group c 64 0x0a0000
chmod 644 group

Create new PV's
pvcreate /dev/rdsk/c3t4d1
pvcreate /dev/rdsk/c4t5d2

Create the volume group using the primary and secondary paths for LUN1

vgcreate /dev/vg10 /dev/dsk/c3t4d1 /dev/dsk/c4t5d1

Activate the VG
vgchange -a y /dev/vg10

Add the 2nd LUN, LUN2, and make sure to flip the primary/secondary paths with respect to LUN1

vgextend /dev/vg10 /dev/dsk/c4t5d2 /dev/dsk/c3t4d2

Now for each logical volume we want to stripe across both LUN's equally so that half the i/o goes through 1 channel and half through the other. This removes all the guesswork about which lvols are busiest. We just throw this at the array and let it sort it out. We just want the UNIX box sending data to it as fast as it can.

lvcreate -i2 -I64 -L100000 -n lvol1 /dev/vg10
lvcreate -i2 -I64 -L20000 -n lvol2 /dev/vg10
and so on for as many LVOL's as you need. This created a 100GB lvol1 and a 20GB lvol2. You can extend this concept across as many I/O chhannels as you like but two should be sufficient.

If you wish to create a filesystem on lvol2:
newfs -F vxfs /dev/vg10/lvol2

I hope I've been clear, Clay

[Keith Lapidus]

Try looking into Veritas VxVM. I have not installed it on any of my HP servers, but we have it installed extensively on our sun environment with EMC and connectrix fiber switches. I believe Veritas calls it DMP(Dynamic Multipathing). It works great because it does all the hard work and presents to you a single path. Behind the scenes, it uses both paths for a theorhetical limit of 200Mbyte/sec throughput.

[Sanjay_6]

Hi Laurie,

As far as channel switching is concerned, once you configure the primary and alternate path, the switching will be automatic in case of primary failure.

AS far as load balancing is convcerned, there is no load balancing for LVM. Here is a thread on LVM / Load balancing,

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=2d056e7d11c0d655a3/screen=ckiDisplayDocument?docId=200000053891763

Hoep this helps.

Regds

[Sanjay_6]

Hi Laurie,

Here is a thread on load balancing on EMC using Powerpath,

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=ffe616a217e5f0e8b6/screen=ckiDisplayDocument?docId=200000055061593

You may think of going into this product if you need load balancing.

Hope this helps.

Regds