mounting disks on other nodes

[nipun_2]

Hi,
I have 4 node clustered environement
with Server , Sat1, Sat2 and Sat3 (disk server).

Sat3 contains database(Volume name - Disk2) which is often accessed by all other above mentioned members

I had a shutdown (due to hardware issue) of Sat3 only and had to reboot it.


When Sat3 came back on I could not see the database on Sat3 from Server. But I could see the database from Sat2 and Sat1.

In this scneario it seems the database volume (Disk2) needs to be mounted

should I use

$MOUNT/SYSTEM/CLUSTER disk2:

or
$ mount /cluster disk2:

and do I have to give the command from the nodes from which I "cannot" see the volume or the other way round. In other words

issue commands from Server or Sat1 (I can see the disk on this node)


Any comments suggestions would be helpful

[David Jones_21]

/cluster always implies /system. It shouldn't make any difference where you issue the mount, though I normally do the mount command on the node where it is not mounted (after making sure the disk is present in the device list).

[John Gillings · Accepted solution]

nipun,

MOUNT/CLUSTER will mount a disk on all reachable cluster members. The disk is mounted system wide on each node (ie: as if it were MOUNT/SYSTEM on that node).

Note that the only way a node cannot "see" a volume is if it were physically attached to another node, and not set "/SERVE", which would be somewhat unusual.

How you manage your disks is a matter of choice, and sometimes needs careful planning, considering all possible combinations and permutations of node boot order. Typically the easiest is to include a MOUNT/CLUSTER of each disk in the startup, and have it executed on every node. However, it should be made conditional on F$GETDVI(device,"EXIST"). I've attached a procedure I use to wait a short time period to see if a device appears.

[John Gillings]

sorry, clicked wrong button, here's the attachment

[Ian Miller.]

small comment on the DCL - I would also check the disk is available F$GETDVI(name,"AVL") before mounting it.

[comarow]

If the system does not have a direct connection to the disk, the disk that has a direct connection must mscp serve the disk.

You must set MSCP_Load=1
and mscp_serve_all= 1
or some reasonable number.

You don't say where the disk is. There are a lot of rules about serving disks. If it's on an hsj or hsc, or a dssi disk the allocation must match up. Log a call and we'll help you.

Bob

[nipun_2]

I have to work on a different issue that is more urgent and will come to this later as this is important in terms of disk usage.

Thank you all for your time