Strange case of vanishing disk

Thomas Mueller mueller23 at
Mon Jun 4 02:38:57 UTC 2012

> this is a very strange issue but I guess will either be related to 2
> things, PSU not being powerful enough or disk controller simply being crap.

> Here's what's going on. I have a little Chenbro 4 disk mini-ITX NAS
> server with 2x 2TB disks and 2x4TB disks as storage - all spread out
> over 2 ZFS storage pools. Additionally I am running the root file system
> on a 40GB SSD.

> The strange thing with this is that I recently installed the 4TB disks
> and they're brand new.

> One disk connected to the system board works fine and shows up as online
> and on one of the channels using atacontrol list.

> The other disk is connected to a Jmicron based 2x SATA RAID
> controller card.

> The disk connected to the controller card is having issues. At first the
> drive wouldn't be seen by the system then after a while all of a sudden
> it was there. No reboots, no io scans nothing it just appeared.

> After blasting it with IO for a few days the disk has now vanished
> again.....

> I had this error in dmesg for a while:

> ad4: TIMEOUT - READ_DMA retrying (1 retry left) LBA=113337535

> I have tried to use pciconf -lbvv to show the connected interfaces and
> the JMICRON comes up fine:

> atapci0 at pci0:2:0:0:    class=0x010400 card=0x2366197b chip=0x2366197b
> rev=0x02 hdr=0x00
>     vendor     = 'JMicron Technology Corp.'
>     device     = 'JMicron JMB366 AHCI/IDE Controller (JMB36X)'
>     class      = mass storage
>     subclass   = RAID
>     bar   [10] = type I/O Port, range 32, base 0xd040, size  8, enabled
>     bar   [14] = type I/O Port, range 32, base 0xd030, size  4, enabled
>     bar   [18] = type I/O Port, range 32, base 0xd020, size  8, enabled
>     bar   [1c] = type I/O Port, range 32, base 0xd010, size  4, enabled
>     bar   [20] = type I/O Port, range 32, base 0xd000, size 16, enabled
>     bar   [24] = type Memory, range 32, base 0xd0510000, size 8192, enabled

> So why isn't the disk?

> I reckon as stated at the beginning that either the 180Watt PSU inside
> the system isn't enough or the controller is just really poor??

> Could anyone suggest anything to look into, I'm sure I've covered all
> the bases but just incase there is something else I can do with this one??

> Thanks.

> Kaya

One thing I can think of is to disconnect the questionable disk from the RAID controller card and connect it directly to the motherboard.

Then you'd know whether the fault is with the hard drive or the RAID controller. 

PSU = power supply unit?  180 watts seems very little, I didn't know any modern system could run on so little.  I thought the minimum would be around 400 watts, and this would not allow for a powerful gaming graphics card.

Maybe you need to replace the power supply with something having more watts, but make sure it will physically fit.


More information about the freebsd-questions mailing list