From: Andrei Borzenkov <arvidjaar@gmail.com>
To: Eric Levy <contact@ericlevy.name>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: race condition mounting multi-device iscsi volume, not resolved in newer kernels
Date: Sat, 22 Jul 2023 09:52:05 +0300 [thread overview]
Message-ID: <7aab044d-30de-5354-e5de-3528a9a4dce3@gmail.com> (raw)
In-Reply-To: <2WO6YR.XUIBVZYBN0GJ1@ericlevy.name>
On 22.07.2023 09:04, Eric Levy wrote:
>
>
> On Sat, Jul 22 2023 at 07:34:26 AM +0300, Andrei Borzenkov
> <arvidjaar@gmail.com> wrote:
>
>> Log with timestamps could be more useful.
>
> I would need to generate a report showing millisecond granularity in
> order to reveal intervals not appearing as zero duration.
>
>> Something tries to mount this filesystem before all its devices are
>> present. You need to find out what does it. btrfs is just a messenger
>> here.
>
> The systemd mount unit is defined to start after iscsi finishes
> initializing.
"iSCSI finishes initializing" just means iscsid was started. The actual
device discovery can take arbitrary amount of time due to network
condition, target behavior and overall system load. So condition "iscsi
finishes initializing" is absolutely wrong for "we can now start
mounting remote devices".
With default btrfs udev rules systemd should wait for device required by
mount unit to become ready; in case of btrfs all devices except the last
discovered one will be "missing" from systemd point of view and only the
last device should allow mount unit to start.
Provide full output of
journalctl -b --no-pager --full
immediately after boot (before doing anything else), it may give some hints.
> The idea that the kernel or filesystem layers wer causing
> problems follows from a remark given to me through a different thread
> that I opened just days ago. I have tried many different variations for
> the systemd mount unit without reaching any success for the issue.
>
Systemd was never designed for dynamic device management when devices
can come and go at arbitrary time and even less for multi-device
filesystems.
next prev parent reply other threads:[~2023-07-22 6:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-22 0:40 race condition mounting multi-device iscsi volume, not resolved in newer kernels Eric Levy
2023-07-22 4:34 ` Andrei Borzenkov
2023-07-22 6:04 ` Eric Levy
2023-07-22 6:52 ` Andrei Borzenkov [this message]
2023-07-22 5:27 ` Torbjörn Jansson
2023-07-22 11:50 ` Anand Jain
2023-07-22 19:07 ` Eric Levy
2023-07-22 19:11 ` Andrei Borzenkov
2023-07-24 3:27 ` Anand Jain
2023-07-24 4:08 ` Eric Levy
2023-07-24 4:42 ` Anand Jain
2023-07-24 6:36 ` Andrei Borzenkov
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