[zfs-discuss] zfs test on external USB connected Hard drive => unstable

Jérôme Lanteri jerome.archlinux at gmail.com
Sat Apr 23 22:11:28 EDT 2016

Yes Tren, i know that the technology works... works while there is no
problem of connection, if there is one, after that (and after connection
has been repair), no more... i think this is the problem.

I suggested, in fact that, in reality (i think the reality of what can
happen in the life has not to be deny when something is madez for
humans), when something USB cabled is connect, if there is no system for
unmount/export automatically when this happen (because this could
happen, and it will happen by the time, it is sure 100%), then the risk
is to have after that commands "zfs" and "zpool" unusable. And that is a
problem to resolve.

So that is why i said, zfs is yet definitly not ready for external HDD
usb connected (or in general, everything is connected and could be
remove/unconnect suddenly).

Now i would like to know if this reality every body could observe and
reproduce, will be considered has a problem (and then be resolved by the
time), or not ?

thank you for your answer Tren.

Le 24/04/16 à 00:27, Tren Blackburn via zfs-discuss a écrit :
> On April 23, 2016 at 9:58:40 AM, Jérôme Lanteri (zfs-discuss at list.zfsonlinux.org(mailto:zfs-discuss at list.zfsonlinux.org)) wrote:
>> I test zfs on external hard drive.
>> creation worked fine
>> read/write ok
>> import on an other computer ok
>> indications about this event connection ok
>> but...
>> sometimes, if the disk is hard unconnected (usb cable move or
>> un-identified disconnection), then it's looks like the hard drive is
>> connected, but:
>> 1: from file browser (GUI), stay on the directory like nothing happen
>> 2: zpool status freeze
>> 3: zpool export freeze
>> 4: zpool clear freeze
>> etc... (all command call zpool/zfs freeze)
>> (lsblk -f doesn't show he device at this time)
>> after see again the device (lsblk -f), command stay blocked, and other
>> freeze same.
>> access on other mounted disks zfs formated stay "on".
>> questions:
>> 1: how to stop command freezing ?
> Ensure your storage is stable and not being disconnected without first exporting the pool
>> 2: do i need to conclude that ZFS is definitly not for usb connected
>> storage devices ?
> It is fine on USB devices, but it expects stable storage. While the pool is imported on that machine, you should take care that you don’t accidentally remove the USB cable.
> HTH, 
> Tren
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