ad WRITE_DMA timing out frequently

[Colin Percival]

Reid Linnemann wrote:
> ad0: TIMEOUT - WRITE_DMA retrying (2 retries left) LBA=2085599
> ad0: TIMEOUT - WRITE_DMA retrying (2 retries left) LBA=2085599
>  kernel: ad0: FAILURE - WRITE_DMA timed out
> kernel: g_vfs_done():ad0s1d[WRITE(offset=52772864, length=16384)]error = 5

Looks like a dying disk.

> It seems to me that a sector on the disk might be dead in the ad0s1d
> slice (/var), but I want to be certain before I take further steps that
> the behavior I'm experiencing is positively unrelated to the migration
> to 6-CURRENT.

Install sysutils/smartmontools from ports and use smartctl.  Odds are that
the drive has logged hundreds of errors by now.

Colin Percival