Tuesday, 22 May 2007

SBS - NTFS Error Event ID 55

One problem we ran into on one of our more data intensive SBS boxes was this:
Event Type: Error
Event Source: Ntfs
Event Category: Disk
Event ID: 55
Date: X/X/XXXX
Time: 7:11:25 AM
User: N/A
Computer: MY-SBS01
The file system structure on the disk is corrupt and unusable. Please run the chkdsk utility on the volume NetworkData.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
The error was on a 1.2 TB RAID 5 array with six 300 GB PATA disks. The sixth drive was a hot spare.

On this particular array, no S.M.A.R.T. errors were thrown. The RAID controller threw no codes before the NTFS error started to show up.

We had to dismount the array and scan it via the following: chkdsk /x /f

The scan took a long time. Once it was finished, the data seemed to be okay.

We did find some corrupted files later on, and found out the hard way that the NTFS failure wiped out the Shadow Copies on the SBS server!

We were fortunate in that we had a live data mirror on a backup server that we were able to recover some of the files from. Some had to be pulled from that server's VSS as the file corruption was passed to it from the SBS server. Anything we couldn't get from the backup server was pulled from tape.

We were at the end of the life cycle of this particular SBS box, so we replaced it with a new Intel SR2400 2U.

When we dismantled the array, a physical scan of each drive in the failed array turned up one with some bad sectors.

It was strange to us that we never saw any signs of the failure coming.

Another reason why multiple levels of redundancy for your client's networks is so very important.

UPDATE: My bad, they were 300 GB drives, not 400 GB. Off to Tims to get all cylinders firing! ;)

Philip Elder
Microsoft Small Business Specialists

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