Network Attached Storage on Service Guard

[Kevin Lamb]

Hi,

I am relatively new to Service Guard and was wondering if anyone had any issues/problems with using NAS in conjunction with M/C Service Guard.

I am looking to replace a Jamaica box which is under SG control betewwn two servers with a NAS device, the filesystems would be NFS mounted to the servers.

Any reported problems/use/issues would be helpful

Thx

Kev

[Santosh Nair_1 · Accepted solution]

I believe you need to have VGs associated with each SG package. With NAS devices, you can't create VGs, you can only mount the already created filesystems. As such, I don't you would be able to replace your jamaica drive, i.e. phyiscally attached storage, with the NAS device.

Hope this helps.

-Santosh

[linuxfan]

Hi Kevin,


As of now i don't believe you can use MC/SG with NAS devices like Netapps, but HP and Netapp (http://www.netapp.com) are coming out with MC/SG capability for netapps

http://www.netapp.com/news/press/2001/news_rel_200010828.html

Not sure what are your packages for but if they are for databases then you may want to take a look at the link

http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0x5f5a1012aa92d5118ff10090279cd0f9,00.html

-HTH
Ramesh

[Kevin Lamb]

Santosh/Ramesh

Thanks for the info, it looks like I will have to move to bigger disks rather than NAS technology.

Thx

Kev

[Matt Szary]

Actually, You don't need to have any vg's associated with a package. Earlier this year, we worked on an MCSG cluster running Oracle OPS. With the db running on both systems at the same time(as OPS does), the vg had to be mounted on both systems at the same time. We had a floating IP for each db, that failed back and forth for the active system and we spread the db's between the systems. Granted, we were using vg's on an EMC, but the logic still follows, as we werent activating any vg's in the package scripts. I don't see why you couldn't mount the nfs fs's on the active system and in the package startup script have it mount the nfs mount point after the floating ip fails over. As far as Netapp performance with db's, we should be testing it out on a demo N class and a Netapp filer in the next month or so.

The OPS solution above was presented at HP World by a friend of mine that I worked on the project with.
http://www.hpworld.com/conference/hpworld2001/sessions/sn043/

[George Petrides]

I am bit confused here. I thought UNIX boxes attach to the Network Attached Storage over NFS. MC/SG supports NFS failover and it should work in a cluster environment. However, you will probably need a shared SCSI/Fibre disk between the two servers to act as the cluster lock (if it's only 2 nodes).

[Duncan Edmonstone]

Of course if you cluster consists of only two nodes, you need a cluster lock disk which must be available to both systems, so you still need some shared disk somewhere.