CentOS

Please forgive any errors or lack of information in this post as I am new to Linux. I am running CentOS 5.5 (Final) - I know it's old but can't upgrade at this time due to a limitation with an application. I have a QNAP NAS with an iSCSI LUN this app accesses. It's been working fine for well over a year but lately my app can't access any data on it. I was getting input\output errors when trying to run "du -hc" on the system which led me to look at the /var/log files (used dmesg command). Pertinent output is below. since this is an external drive system mounted on /mnt/iscsi3, can I run fsck against it? Thanks.

Vendor: QNAP Model: iSCSI Storage Rev: 4.0
Type: Direct-Access ANSI SCSI revision: 05
sdc : very big device. try to use READ CAPACITY(16).
SCSI device sdc: 14656995328 512-byte hdwr sectors (7504382 MB)
sdc: Write Protect is off
sdc: Mode Sense: 2f 00 10 00
SCSI device sdc: drive cache: write back w/ FUA
sdc : very big device. try to use READ CAPACITY(16).
SCSI device sdc: 14656995328 512-byte hdwr sectors (7504382 MB)
sdc: Write Protect is off
sdc: Mode Sense: 2f 00 10 00
SCSI device sdc: drive cache: write back w/ FUA
sdc:<4>GPT:Primary header thinks Alt. header is not at the end of the disk.
GPT:11624513535 != 14656995327
GPT:Alternate GPT header not at the end of the disk.
GPT:11624513535 != 14656995327
GPT: Use GNU Parted to correct GPT errors.
sdc1
sd 6:0:0:0: Attached scsi disk sdc
sd 6:0:0:0: Attached scsi generic sg8 type 0
EXT4-fs (sdc1): warning: mounting fs with errors, running e2fsck is recommended
EXT4-fs (sdc1): recovery complete
EXT4-fs (sdc1): mounted filesystem with ordered data mode
Bluetooth: HIDP (Human Interface Emulation) ver 1.1
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
NFSD: starting 90-second grace period
fuse init (API version 7.10)
kjournald starting. Commit interval 5 seconds
EXT3-fs warning: checktime reached, running e2fsck is recommended
EXT3 FS on sda2, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
EXT4-fs error (device sdc1): ext4_lookup: deleted inode referenced: 173969136
EXT4-fs error (device sdc1): ext4_lookup: deleted inode referenced: 169972535
EXT4-fs error (device sdc1): ext4_lookup: deleted inode referenced: 169972533

5.5 is not just OLD, it's ANCIENT and really really shouldn't be used. At the very least you should be thinking about updating that to 5.11 which is "only" 8 months out of date rather than the 6 or 7 years that 5.5 is!

CentOS 5 is EOL and unsupported. Migrate to something newer. Sooner rather than later. It's a liability.

I realize it's old. We have wanted to upgrade for a while but the app running on the server doesn't support anything above it. And it's going away in the next 6 months so not worth my time. I just want to get access to the data to make a good copy before we transition to a new system. But I need to get to the data first.

Did you run e2fsck like it suggested? If this is valuable data, might want to back the iscsi image file up on the NAS before you do.