View Full Version : Partition keeps "disappearing"

26th October 2007, 10:30 PM

My /dev/sdb1 keeps "disappearing". As in, MDADM says it can't find it. if I ls -l in /dev, i only see sdb.

If I run "fdisk -l", I can see my sdb and the partition there and it's fine. if I "fdisk /dev/sdb", and do nothing except write the partition table (untouched), it then shows up in /dev, and mdadm has no problems mounting it.

What the heck is going on?

Anytime I reboot, the partition goes "missing" even though it's still there!!! I'm going nuts!

27th October 2007, 01:44 AM
Normally (I assume this is an internal hard disk) the partition table is observed when the kernel starts up and the drive is initialized. mdadm, by default looks through /proc/partitions.

It sounds like your disk (or at least block 0), is unreadable at initialization.

After you fdisk & write and the partition re-appears - does the partition later disappear again ?
If so it sounds like somehow the driver is re-init'ing and at that time it caqnnot read block0.

Do any messages appear in dmesg ?
Perhaps there is a long-period disk test that would show the problem. Try the disk mfgr's
web site, as they sometimes have good diags. If the disk supports SMART, then run the
smart daemon and check the logs..