Hi list,
I have just discovered that there is a race condition when we put /var/lib/sssd on NFSv4 volume (such as in diskless boot scenario). System tends to hang randomly. Is there any solution to this? Only cure seems to me at the moment to mount it via NFSv3 which does not require idmapper.
Thanks, Ondrej
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On Wed, Sep 16, 2015 at 07:21:17AM +0000, Ondrej Valousek wrote:
Hi list,
I have just discovered that there is a race condition when we put /var/lib/sssd on NFSv4 volume (such as in diskless boot scenario). System tends to hang randomly. Is there any solution to this? Only cure seems to me at the moment to mount it via NFSv3 which does not require idmapper.
Simo or other more seasoned Samba developers might know better, but IIRC tdb (the underlying key-value store our ldb cache uses) wasn't usable well on NFS due to some locking issues..
On (16/09/15 09:29), Jakub Hrozek wrote:
On Wed, Sep 16, 2015 at 07:21:17AM +0000, Ondrej Valousek wrote:
Hi list,
I have just discovered that there is a race condition when we put /var/lib/sssd on NFSv4 volume (such as in diskless boot scenario). System tends to hang randomly. Is there any solution to this? Only cure seems to me at the moment to mount it via NFSv3 which does not require idmapper.
Simo or other more seasoned Samba developers might know better, but IIRC tdb (the underlying key-value store our ldb cache uses) wasn't usable well on NFS due to some locking issues..
So the solution/workaround is to mount tmpfs on /var/lib/sss/db/ on diskless machines.
LS
Well, I do not want to do that for a single reason: SSSD is unfortunately still buggy enough to go offline (at least chances are high) when machine is restarted. With tmpfs, my automouter would be busted that way and several serviced would not start properly.
Luckily enough, there is still an option to mount it via NFSv3. That way, even if sssd goes offline, it still has sufficient data in cache for automounter to start properly.
Ondrej
-----Original Message----- From: sssd-users-bounces@lists.fedorahosted.org [mailto:sssd-users-bounces@lists.fedorahosted.org] On Behalf Of Lukas Slebodnik Sent: 18 September 2015 09:54 To: End-user discussions about the System Security Services Daemon sssd-users@lists.fedorahosted.org Subject: Re: [SSSD-users] Race condition when /var/lib/sssd in on NFSv4
On (16/09/15 09:29), Jakub Hrozek wrote:
On Wed, Sep 16, 2015 at 07:21:17AM +0000, Ondrej Valousek wrote:
Hi list,
I have just discovered that there is a race condition when we put /var/lib/sssd on NFSv4 volume (such as in diskless boot scenario). System tends to hang randomly. Is there any solution to this? Only cure seems to me at the moment to mount it via NFSv3 which does not require idmapper.
Simo or other more seasoned Samba developers might know better, but IIRC tdb (the underlying key-value store our ldb cache uses) wasn't usable well on NFS due to some locking issues..
So the solution/workaround is to mount tmpfs on /var/lib/sss/db/ on diskless machines.
LS _______________________________________________ sssd-users mailing list sssd-users@lists.fedorahosted.org https://lists.fedorahosted.org/mailman/listinfo/sssd-users
-----
The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications@s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18.
On Fri, 2015-09-18 at 08:03 +0000, Ondrej Valousek wrote:
Well, I do not want to do that for a single reason: SSSD is unfortunately still buggy enough to go offline (at least chances are high) when machine is restarted. With tmpfs, my automouter would be busted that way and several serviced would not start properly.
Luckily enough, there is still an option to mount it via NFSv3. That way, even if sssd goes offline, it still has sufficient data in cache for automounter to start properly.
Up to you, but you are trading a known issue, for unknown issues and corruption that may crop up and be undebuggable.
Simo.
Ondrej
-----Original Message----- From: sssd-users-bounces@lists.fedorahosted.org [mailto:sssd-users-bounces@lists.fedorahosted.org] On Behalf Of Lukas Slebodnik Sent: 18 September 2015 09:54 To: End-user discussions about the System Security Services Daemon sssd-users@lists.fedorahosted.org Subject: Re: [SSSD-users] Race condition when /var/lib/sssd in on NFSv4
On (16/09/15 09:29), Jakub Hrozek wrote:
On Wed, Sep 16, 2015 at 07:21:17AM +0000, Ondrej Valousek wrote:
Hi list,
I have just discovered that there is a race condition when we put /var/lib/sssd on NFSv4 volume (such as in diskless boot scenario). System tends to hang randomly. Is there any solution to this? Only cure seems to me at the moment to mount it via NFSv3 which does not require idmapper.
Simo or other more seasoned Samba developers might know better, but IIRC tdb (the underlying key-value store our ldb cache uses) wasn't usable well on NFS due to some locking issues..
So the solution/workaround is to mount tmpfs on /var/lib/sss/db/ on diskless machines.
LS _______________________________________________ sssd-users mailing list sssd-users@lists.fedorahosted.org https://lists.fedorahosted.org/mailman/listinfo/sssd-users
The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications@s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18. _______________________________________________ sssd-users mailing list sssd-users@lists.fedorahosted.org https://lists.fedorahosted.org/mailman/listinfo/sssd-users
Understood. Once SSSD is in shape good enough for it. I will put /var/lib/sssd on tmpfs. For now, I have to decide between two bad options. O.
-----Original Message----- From: sssd-users-bounces@lists.fedorahosted.org [mailto:sssd-users-bounces@lists.fedorahosted.org] On Behalf Of Simo Sorce Sent: Tuesday, September 22, 2015 3:23 PM To: End-user discussions about the System Security Services Daemon sssd-users@lists.fedorahosted.org Subject: Re: [SSSD-users] Race condition when /var/lib/sssd in on NFSv4
On Fri, 2015-09-18 at 08:03 +0000, Ondrej Valousek wrote:
Well, I do not want to do that for a single reason: SSSD is unfortunately still buggy enough to go offline (at least chances are high) when machine is restarted. With tmpfs, my automouter would be busted that way and several serviced would not start properly.
Luckily enough, there is still an option to mount it via NFSv3. That way, even if sssd goes offline, it still has sufficient data in cache for automounter to start properly.
Up to you, but you are trading a known issue, for unknown issues and corruption that may crop up and be undebuggable.
Simo.
Ondrej
-----Original Message----- From: sssd-users-bounces@lists.fedorahosted.org [mailto:sssd-users-bounces@lists.fedorahosted.org] On Behalf Of Lukas Slebodnik Sent: 18 September 2015 09:54 To: End-user discussions about the System Security Services Daemon sssd-users@lists.fedorahosted.org Subject: Re: [SSSD-users] Race condition when /var/lib/sssd in on NFSv4
On (16/09/15 09:29), Jakub Hrozek wrote:
On Wed, Sep 16, 2015 at 07:21:17AM +0000, Ondrej Valousek wrote:
Hi list,
I have just discovered that there is a race condition when we put /var/lib/sssd on NFSv4 volume (such as in diskless boot scenario). System tends to hang randomly. Is there any solution to this? Only cure seems to me at the moment to mount it via NFSv3 which does not require idmapper.
Simo or other more seasoned Samba developers might know better, but IIRC tdb (the underlying key-value store our ldb cache uses) wasn't usable well on NFS due to some locking issues..
So the solution/workaround is to mount tmpfs on /var/lib/sss/db/ on diskless machines.
LS _______________________________________________ sssd-users mailing list sssd-users@lists.fedorahosted.org https://lists.fedorahosted.org/mailman/listinfo/sssd-users
The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications@s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18. _______________________________________________ sssd-users mailing list sssd-users@lists.fedorahosted.org https://lists.fedorahosted.org/mailman/listinfo/sssd-users
-- Simo Sorce * Red Hat, Inc * New York
_______________________________________________ sssd-users mailing list sssd-users@lists.fedorahosted.org https://lists.fedorahosted.org/mailman/listinfo/sssd-users
-----
The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications@s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18.
On Wed, 23 Sep 2015, Ondrej Valousek wrote:
Understood. Once SSSD is in shape good enough for it. I will put /var/lib/sssd on tmpfs. For now, I have to decide between two bad options.
Could you not whip the cache into a shape where it masks your issue, then save that to pre-populate the tmpfs?
jh
On Wed, 2015-09-16 at 09:29 +0200, Jakub Hrozek wrote:
On Wed, Sep 16, 2015 at 07:21:17AM +0000, Ondrej Valousek wrote:
Hi list,
I have just discovered that there is a race condition when we put /var/lib/sssd on NFSv4 volume (such as in diskless boot scenario). System tends to hang randomly. Is there any solution to this? Only cure seems to me at the moment to mount it via NFSv3 which does not require idmapper.
Simo or other more seasoned Samba developers might know better, but IIRC tdb (the underlying key-value store our ldb cache uses) wasn't usable well on NFS due to some locking issues..
NFS may have locking issues, also tdb uses mmap, which is also not great over NFS. In general putting a LOCAL cache over the network is just not a good move.
Put it in tmpfs if you do not have a disk, and just regen it every time, putting /var/lib/sss on NFS is just a good way to have (very) bad performance and various issues with the databases in it.
Simo.
sssd-users@lists.fedorahosted.org
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Jakub Hrozek -
John Hodrien -
Lukas Slebodnik -
Ondrej Valousek -
Simo Sorce