On Thu, 2 Feb 2012 04:50:06 +0000 "Vlasov, Vladimir" <vvlasov@xxxxxxx> wrote: > Well, nobody deal with HA Linux clusters? I certainly don't. And like I said before - you are a SUSE customer and you are using a SUSE product so your best best it to ask SUSE for help. The in-kernel 'statd' which you are fighting with is a SUSE-specific innovation (which I thankfully got rid of in later products) so no-one here is going to be likely to help you with it. NeilBrown > > Best regards > Vladimir Vlasov > -----Original Message----- > From: linux-nfs-owner@xxxxxxxxxxxxxxx [mailto:linux-nfs-owner@xxxxxxxxxxxxxxx] On Behalf Of Vlasov, Vladimir > Sent: Friday, January 27, 2012 12:32 PM > To: NeilBrown > Cc: linux-nfs@xxxxxxxxxxxxxxx > Subject: RE: Re-init lockd and kstatd in runtime. > > Finally I have found notes on HA NFS on SLES9 - http://www.gatsby.ucl.ac.uk/~johnp/compute/ha-nfs-sles9.html > There are more info on this topic, for instance http://linux-ha.org/DRBD/NFS Suddenly I realized that previous designer was following these guidelines :-) > > I have found that all documents suggest to have both primary and standby hosts configured as NFS server only and start/stop server processes when role is changed. > This way /var/lib/nfs, even relocating on DRBD partition, is always available on NFS server startup. > So, it is OK to have /var/lib/nfs as link to the folder on DRBD partition. > > What I have different is that my system breaks rule of acting as NFS servers only: standby host acts as NFS client until it becomes primary, then it should act as server. > > > I'll summarize info here: > "server" is DNS record, resolved into IP of the primary host. > > HOST1, primary: > /dev/drbd is mounted as /storage > /storage is exported > server:/storage is mounted as /some/path /var/lib/nfs is link to the /some/path/var/lib/nfs and is available > > HOST2: > /dev/drbd is not mounted, /storage is empty server:/storage is mounted as /some/path /var/lib/nfs is link to the /some/path/var/lib/nfs and is empty > > So, due to this /some/path mount existing on both hosts I have problem with initialization of the kstatd on the standby host, where /var/lib/nfs looks like empty folder. > I have requirement for having /some/path on both hosts, so I can't fallback to guidelines advices. > I need to do NFS client became NFS server somehow. There should be some runtime re-initialization. This is what I'm looking for. > > Could someone comment on this? > Is there any way to do so? > Or any better solution? > > By the way, browsing sources I have found that one can set nsm_use_kstatd to 1 on lockd exit, then initialization will be successful on next mount or export attempts. > I think someone can find it useful so created patch. Unfortunately I don't have neither time nor enough code knowledge. > In my case this proposal has drawback - lockd exits when all mounts are unmounted only, so I have to umount /some/path first and then mount it back. > It can be painful as soon as some files can be opened by local user and umount will complain with it's usual "device is busy". > > Also I was thinking about having /var/lin/nfs locally, separate for each host, so kstatd will be initialized always, but how do I share vital info about clients then? > I have found it to be dead-end. > > > Best regards > Vladimir Vlasov > > -----Original Message----- > From: Vlasov, Vladimir > Sent: Thursday, January 26, 2012 4:14 PM > To: 'NeilBrown' > Cc: linux-nfs@xxxxxxxxxxxxxxx > Subject: RE: Re-init lockd and kstatd in runtime. > > Yes, it is SLES10 SP3 and I'm a customer. > I'm not sure that Novell can help me, I expect the same proposal from them - "just make sure that /var/lib/nfs is available on startup". > I'm not satisfied with this because I have some kind of high availability system built with two Linux hosts. > > Hosts share DRBD partition and one acting as primary exports, for instance /some/path. > As soon as primary host fails, another one becomes primary and exports /some/path. > There are more hosts on the network, they mount: > server:/some/path > where "server" is resolved to the IP of current primary host which currently exports path. > > So, in order to keep and overtake data about clients, /var/lib/nfs is replaced with link and points to /some/path/var/lib/nfs. > If You don't familiar with DRBD then the most important thing You should know is that it is available for R/W on primary host only. > So, on primary host DRBD is R/W, /var/lib/nfs is available and kstatd starts. > On another host DRBD is NOT R/W, /var/lib/nfs is empry and kstatd doesn't start. > This is why I'm looking for how do I re-init it at any time. > > I was looking for guidelines of using NFS in clusters but didn't found anything useful. > > Best regards > Vladimir Vlasov > > -----Original Message----- > From: NeilBrown [mailto:neilb@xxxxxxx] > Sent: Thursday, January 26, 2012 3:41 PM > To: Vlasov, Vladimir > Cc: linux-nfs@xxxxxxxxxxxxxxx > Subject: Re: Re-init lockd and kstatd in runtime. > > On Thu, 26 Jan 2012 11:15:02 +0000 "Vlasov, Vladimir" <vvlasov@xxxxxxx> wrote: > > > Hi. > > > > I'm wondering if there is any way to re-init lockd and kstatd after startup? > > > > Look, in svc.c static variable nsm_use_kstatd is set to 1. > > Then, if nsm_kernel_statd_init() returns error, nsm_use_kstatd is set to 0. > > And we end up without kstatd. > > > > Lockd will exit as soon as last NFS mount is unmounted and on next mount attempt lockd() in svc.c will be called again, but nsm_use_kstatd is 0 already and kstatd init will be skipped. > > > > So, looks like if /var/lib/nfs/state is missed on host startup, there is no way to recover and tell kernel init kstatd later on demand. Or? > > This would be SLES10 - correct? > > I suggest you simply make sure /var/lib/nfs/state is not missing at startup. > > The issue sounds vaguely familiar ... maybe it is fixed in SLES10-SP4... > > What release are you running? Are you a SLES customer? If you are, you would be better off logging a support request on the SUSE bugzilla (bugzilla.novell.com). > > NeilBrown > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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