SAN Disk w/o Cluster

Applications Filesystems, Disks and Memory
1

Scenario:

I've got 2 M5000's connected to a 9985 SAN storage array. I have configured the SAN disks with stmsboot, format and newfs. I can access the same SAN space from both systems. I have created files from both systems on the SAN space.

Question:

Why can't I see the file created with "SystemA" from "SystemB"?

SystemA:

root@SystemA# df -h
Filesystem             size   used  avail capacity  Mounted on
...
/dev/dsk/c6t60060E80144380000001438000000342d0s3
                        15G    15M    15G     1%    /c3d10
root@SystemA# ls -lsa /c3d10
total 204996
   2 drwxr-xr-x   3 oracle   dba          512 Apr 24 10:29 .
   2 drwxr-xr-x  34 root     root        1024 Apr 24 14:32 ..
41008 -rw------T   1 root     root     20971520 Apr 24 13:15 20mtest
61488 -rw------T   1 root     root     31457280 Apr 24 13:15 30mtest
102480 -rw------T   1 root     root     52428800 Apr 24 14:42 50mtest
  16 drwx------   2 root     root        8192 Apr 14 15:26 lost+found
root@SystemA# mkfile 7m /c3d10/7mtest
root@SystemA# ls -lsa /c3d10
total 219348
   2 drwxr-xr-x   3 oracle   dba          512 Apr 27 09:48 .
   2 drwxr-xr-x  34 root     root        1024 Apr 27 09:47 ..
41008 -rw------T   1 root     root     20971520 Apr 24 13:15 20mtest
61488 -rw------T   1 root     root     31457280 Apr 24 13:15 30mtest
102480 -rw------T   1 root     root     52428800 Apr 24 14:42 50mtest
14352 -rw------T   1 root     root     7340032 Apr 27 09:48 7mtest
  16 drwx------   2 root     root        8192 Apr 14 15:26 lost+found

SystemB:

root@SystemB# df -h
Filesystem             size   used  avail capacity  Mounted on
...
/dev/dsk/c6t60060E80144380000001438000000342d0s3
                        15G    65M    15G     1%    /c3d10
root@SystemB# ls -lsa /c3d10
total 204996
   2 drwxr-xr-x   3 oracle   dba          512 Apr 24 14:42 .
   2 drwxr-xr-x  34 root     root        1024 Apr 24 14:32 ..
41008 -rw------T   1 root     root     20971520 Apr 24 13:15 20mtest
61488 -rw------T   1 root     root     31457280 Apr 24 13:15 30mtest
102480 -rw------T   1 root     root     52428800 Apr 24 14:42 50mtest
  16 drwx------   2 root     root        8192 Apr 14 15:26 lost+found

Any help is greatly appreciated!

2

If two systems view the SAME filesystem (even if one is read only), you have to run a cluster aware filesystem.

In your case (I believe) shared drive w/o cluster isn't really possible. Cluster the boxes (at least filesystem wise) and run a cluster aware filesystem. Most of the filesystems supplied by *ix vendors are NOT cluster aware.

3

Well file systems need not be cluster aware. I can have 2 drives presented to both systems at same time but have only one fs write to that shared disk.

4

You CAN have both be able to have ACCESS to the drive. However, it is NOT true that one can be read+write and the other read only. The only way this is safe is if one system is NOT using (and if possible, seeing) the drive at the same time. Why? Because manipulations to the drive can happen from the system that has read+write including modifications to meta data areas... and if that information is not communicated somehow to the other host, then even if it's supposedly "read only", you'll be messing up the internal representation on that host and possible cause issues, perhaps major issues.