External Storage (NFS mount) not available -> owncloud crashes

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External Storage (NFS mount) not available -> owncloud crashes

Thomas Keil
Hello,

I have a raspberry pi running owncloud, and a fileserver in the same
network, which is mounted via NFS on the pi. this storage is then
mounted as 'local' in owncloud.
the problem comes in when the fileserver is offline. if I try to access
a folder from the NFS mount (which is not available since the server is
down), owncloud hangs completely. the apache itself is still running,
other hosted sites are available, but I have to restart the apache
server to be able to access owncloud again.

my setup is still experimental. I have two synchronized owncloud
instances, one on the pi and one on the fileserver. I use LDAP
authentication (the server is running 24/7 on the pi) for both
instances. the file system structure concerning owncloud is identical
for both machines. the directory which is mounted as 'external storage'
is exported as NFS from the fileserver to the pi. the mysql databases
are synchronized via master-master replication, the data directory via
unison.
it is working fine when both machines are running. the only problem (for
now) is the one described above.

is there a better approach to handle this situation? I would like to
avoid using SMB (for technical as well as personal reasons), and SFTP
does not work (or at least I did not get it to work for now).

I would really appreciate comments or suggestions concerning this
problem. I also welcome questions about my setup in general (which I
will gladly describe in detail once it is working satisfactorily).


kind regards,

Thomas Keil

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Re: External Storage (NFS mount) not available -> owncloud crashes

Jörn Friedrich Dreyer-2
There are several things you can try. Out of my head I remember two relevant mount options:
- stale, which should handle an offline fileserver more graceful. That might however not solve the problem of owncloud locking up when trying to access the file, because we internally cache all the metadata and then of course expect the files the be available.
- fsc, which makes nfs mount use FSCACHE when the cachefilesd is running and configured. I don't know if that is available on the pi.

In general oc makes the assumption that file modifications are made exclusively via webdav or the web frontend. If I understand correctly you are using a replicated mysql setup on the two machines an then use nfs to export the files from the fileserver to the pi. That should work, assuming you mount the NFS share as the data dir and point the logfile to another directory on the pi.

I do not understand what you mean by external starage mounted as local because those terms are used in several places and I might likely misinterpret what you are saying.

Have you set up cachefilesd?
What mount options do you use?
Where do you mount the nfs share in relation to the owncloud data dir on the pi?
Do you use the files_external app?

So long

Jörn



Thomas Keil <[hidden email]> schrieb:
Hello,

I have a raspberry pi running owncloud, and a fileserver in the same
network, which is mounted via NFS on the pi. this storage is then
mounted as 'local' in owncloud.
the problem comes in when the fileserver is offline. if I try to access
a folder from the NFS mount (which is not available since the server is
down), owncloud hangs completely. the apache itself is still running,
other hosted sites are available, but I have to restart the apache
server to be able to access owncloud again.

my setup is still experimental. I have two synchronized owncloud
instances, one on the pi and one on the fileserver. I use LDAP
authentication (the server is running 24/7 on the pi) for both
instances. the file system structure concerning owncloud is identical
for both machines. the directory which is mounted as 'external storage'
is exported as NFS from the fileserver to the pi. the my sql databases
are synchronized via master-master replication, the data directory via
unison.
it is working fine when both machines are running. the only problem (for
now) is the one described above.

is there a better approach to handle this situation? I would like to
avoid using SMB (for technical as well as personal reasons), and SFTP
does not work (or at least I did not get it to work for now).

I would really appreciate comments or suggestions concerning this
problem. I also welcome questions about my setup in general (which I
will gladly describe in detail once it is working satisfactorily).


kind regards,

Thomas Keil



Owncloud mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/owncloud

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Re: External Storage (NFS mount) not available -> owncloud crashes

Thomas Keil
Thank you for your reply, and sorry for being unclear about the
mounting. On the pi I mount the NFS share to /mnt/disk1. The owncloud
data directory is inside the owncloud directory,
in /var/server/owncloud/data.
I then use the files_external app to mount subdirectories of /mnt/disk1
(my NFS share) into owncloud. This is what I mean by 'local' since this
looks like a local folder to owncloud.
I have no cachefilesd set up (until now I did not know it exists), and
the man-page of nfs on the pi does not contain the 'fsc' option, so I
guess it might not be available on raspbian.

The fstab-Entry for the NFS mount is:

fileserver:/mnt/disk1     /mnt/disk1      nfs     rw,soft 0       0

The 'soft' option should be what you meant with 'stale'. The 'mount'
command gives the following result (with inserted line breaks):

fileserver:/mnt/disk1 on /mnt/disk1 type nfs4
(rw,relatime,vers=4.0,rsize=1048576,wsize=1048576,
namlen=255,soft,proto=tcp,port=0,timeo=600,retrans=2,
sec=sys,clientaddr=192.168.2.23,local_lock=none,addr=192.168.2.24)

Here the timeout for the nfs mount is set to 600 seconds. I just set
this to 10 seconds, and now owncloud just silently fails to open the
corresponding directories. This is the behaviour I was aiming for, so
probably my problem is solved by now :)
I think that owncloud was locked by the timeout of the nfs client trying
to reach the server. I never tried to wait 10 minutes for owncloud to
respond.

Many thanks again for the helpful questions!

Kind regards,

Thomas


On Tue, 2013-10-29 at 09:52 +0100, Jörn Friedrich Dreyer wrote:

> There are several things you can try. Out of my head I remember two
> relevant mount options:
> - stale, which should handle an offline fileserver more graceful. That
> might however not solve the problem of owncloud locking up when trying
> to access the file, because we internally cache all the metadata and
> then of course expect the files the be available.
> - fsc, which makes nfs mount use FSCACHE when the cachefilesd is
> running and configured. I don't know if that is available on the pi.
>
> In general oc makes the assumption that file modifications are made
> exclusively via webdav or the web frontend. If I understand correctly
> you are using a replicated mysql setup on the two machines an then use
> nfs to export the files from the fileserver to the pi. That should
> work, assuming you mount the NFS share as the data dir and point the
> logfile to another directory on the pi.
>
> I do not understand what you mean by external starage mounted as local
> because those terms are used in several places and I might likely
> misinterpret what you are saying.
>
> Have you set up cachefilesd?
> What mount options do you use?
> Where do you mount the nfs share in relation to the owncloud data dir
> on the pi?
> Do you use the files_external app?
>
> So long
>
> Jörn
>
>
>
> Thomas Keil <[hidden email]> schrieb:
>         Hello,
>        
>         I have a raspberry pi running owncloud, and a fileserver in the same
>         network, which is mounted via NFS on the pi. this storage is then
>         mounted as 'local' in owncloud.
>         the problem comes in when the fileserver is offline. if I try to access
>         a folder from the NFS mount (which is not available since the server is
>         down), owncloud hangs completely. the apache itself is still running,
>         other hosted sites are available, but I have to restart the apache
>         server to be able to access owncloud again.
>        
>         my setup is still experimental. I have two synchronized owncloud
>         instances, one on the pi and one on the fileserver. I use LDAP
>         authentication (the server is running 24/7 on the pi) for both
>         instances. the file system structure concerning owncloud is identical
>         for both machines. the directory which is mounted as 'external storage'
>         is exported as NFS from the fileserver to the pi. the my
>          sql
>         databases
>         are synchronized via master-master replication, the data directory via
>         unison.
>         it is working fine when both machines are running. the only problem (for
>         now) is the one described above.
>        
>         is there a better approach to handle this situation? I would like to
>         avoid using SMB (for technical as well as personal reasons), and SFTP
>         does not work (or at least I did not get it to work for now).
>        
>         I would really appreciate comments or suggestions concerning this
>         problem. I also welcome questions about my setup in general (which I
>         will gladly describe in detail once it is working satisfactorily).
>        
>        
>         kind regards,
>        
>         Thomas Keil
>        
>        
>         ______________________________________________________________
>        
>         Owncloud mailing list
>         [hidden email]
>         https://mail.kde.org/mailman/listinfo/owncloud
>
> _______________________________________________
> Owncloud mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/owncloud

_______________________________________________
Owncloud mailing list
[hidden email]
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