Data in SAN Drive appers and disapperas intermittently

I have two 3PAR SAN LUN’s assigned to a IBM blade working on RHEL 5.3 , Both LUN drives are mounted on  drives as below
{my_data on /dev/dem-0   and my_backup /dev/dm-1}
[root@rhel4 /]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2             9.3G  1.8G  7.0G  21% /
/dev/sda8             3.9G   79M  3.6G   3% /tmp
/dev/sda7             9.3G  3.5G  5.3G  40% /usr
/dev/sda5              35G   12G   22G  36% /backup
/dev/sda3              42G  9.4G   31G  24% /my_db
/dev/sda1             2.0G   42M  1.8G   3% /boot
tmpfs                 5.9G   34M  5.9G   1% /dev/shm
/dev/dm-0             296G  264G   17G  94% /my_data
/dev/dm-1             296G   49G  232G  18% /my_backup
Mutip[athing have been configured and is with below output
[root@rhel4 /]# multipath -ll
Cannot open /proc/sys/fs/nr_open : No such file or directory
360002ac0000000000000033300007f21 dm-1 3PARdata,VV
size=300G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
  |- 2:0:1:0  sde 8:64 active ready running
  `- 2:0:0:0  sdc 8:32 active ready running
360002ac0000000000000066600007f21 dm-0 3PARdata,VV
size=300G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
  |- 2:0:1:1  sdf 8:80 active ready running
  `- 2:0:0:1  sdd 8:48 active ready running
My issue is that my files in SAN drive (/my_data/db/apps_st/data) disappearing and appearing automatically, that also not always -but intermittently.   It’s only file that disappear, Drive and drive path still remains.  

Kindly guide what is happening to my infrastructure , any thought’s will be highly appreciated
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Joshua HopkinsPresidentCommented:
Sounds like a communication problem either on the fabric side or with the internals (network interfaces, storage controller, drive connectors, or the harddrives) of the 3par system.
SHBSystems ArchitectCommented:
from the command, it shows only two paths are there to the SAN disk.

Can you give me which firmware the storage is running.

Also if you have access to 3PAR, please run the command showhost <hostname>

it will list the paths. And you have to see if the paths are via both switches.

Is the round robin policy has been set on the host side?
andyalderSaggar maker's framemakerCommented:
If you umount and then mount it again does the list of files change?
FiruITAuthor Commented:
it fixed by itself when , we reinstalled everything

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