>
> Hm, the same test worked for me with version 16.2.13... I mean, I only
> do a few writes from a single client, so this may be an invalid test,
> but I don't see any interruption.
I tried many times and I'm sure that my test is correct.
Yes, write can be active for some time after rank 1 went down, maybe tens
seconds. And listing files (ls) can work some time for dirs which were
listed before rank down, but only fews seconds.
Before shutdown rank 1 I run write in this way:
while true; do dd if=/dev/vda of=/cephfs-mount/dir1/`uuidgen` count=1
oflag=direct; sleep 0.000001; done
Maybe it depends on the RPS...
пт, 22 нояб. 2024 г. в 14:48, Eugen Block <eblock@xxxxxx>:
> Hm, the same test worked for me with version 16.2.13... I mean, I only
> do a few writes from a single client, so this may be an invalid test,
> but I don't see any interruption.
>
> Zitat von Eugen Block <eblock@xxxxxx>:
>
> > I just tried to reproduce the behaviour but failed to do so. I have
> > a Reef (18.2.2) cluster with multi-active MDS. Don't mind the
> > hostnames, this cluster was deployed with Nautilus.
> >
> > # mounted the FS
> > mount -t ceph nautilus:/ /mnt -o
> > name=admin,secret=****,mds_namespace=secondfs
> >
> > # created and pinned directories
> > nautilus:~ # mkdir /mnt/dir1
> > nautilus:~ # mkdir /mnt/dir2
> >
> > nautilus:~ # setfattr -n ceph.dir.pin -v 0 /mnt/dir1
> > nautilus:~ # setfattr -n ceph.dir.pin -v 0 /mnt/dir2
> >
> > I stopped all standby daemons while writing into /mnt/dir1, then I
> > also stopped rank 1. But the writes were not interrupted (until I
> > stopped them). You're on Pacific, I'll see if I can reproduce it
> > there.
> >
> > Zitat von Александр Руденко <a.rudikk@xxxxxxxxx>:
> >
> >>>
> >>> Can you show the entire 'ceph fs status' output? Any maybe also 'ceph
> >>> fs dump'?
> >>
> >>
> >> Nothing special, just smoll test cluster.
> >> fs1 - 10 clients
> >> ===
> >> RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS
> >> 0 active a Reqs: 0 /s 18.7k 18.4k 351 513
> >> 1 active b Reqs: 0 /s 21 24 16 1
> >> POOL TYPE USED AVAIL
> >> fs1_meta metadata 116M 3184G
> >> fs1_data data 23.8G 3184G
> >> STANDBY MDS
> >> c
> >>
> >>
> >> fs dump
> >>
> >> e48
> >> enable_multiple, ever_enabled_multiple: 1,1
> >> default compat: compat={},rocompat={},incompat={1=base v0.20,2=client
> >> writeable ranges,3=default file layouts on dirs,4=dir inode in separate
> >> object,5=mds uses versioned encoding,6=dirfrag is stored in omap,8=no
> >> anchor table,9=file layout v2,10=snaprealm v2}
> >> legacy client fscid: 1
> >>
> >> Filesystem 'fs1' (1)
> >> fs_name fs1
> >> epoch 47
> >> flags 12
> >> created 2024-10-15T18:55:10.905035+0300
> >> modified 2024-11-21T10:55:12.688598+0300
> >> tableserver 0
> >> root 0
> >> session_timeout 60
> >> session_autoclose 300
> >> max_file_size 1099511627776
> >> required_client_features {}
> >> last_failure 0
> >> last_failure_osd_epoch 943
> >> compat compat={},rocompat={},incompat={1=base v0.20,2=client writeable
> >> ranges,3=default file layouts on dirs,4=dir inode in separate
> object,5=mds
> >> uses versioned encoding,6=dirfrag is stored in omap,7=mds uses inline
> >> data,8=no anchor table,9=file layout v2,10=snaprealm v2}
> >> max_mds 2
> >> in 0,1
> >> up {0=12200812,1=11974933}
> >> failed
> >> damaged
> >> stopped
> >> data_pools [7]
> >> metadata_pool 6
> >> inline_data disabled
> >> balancer
> >> standby_count_wanted 1
> >> [mds.a{0:12200812} state up:active seq 13 addr [v2:
> >> 10.7.1.115:6842/1955635987,v1:10.7.1.115:6843/1955635987] compat
> >> {c=[1],r=[1],i=[7ff]}]
> >> [mds.b{1:11974933} state up:active seq 5 addr [v2:
> >> 10.7.1.116:6840/536741454,v1:10.7.1.116:6841/536741454] compat
> >> {c=[1],r=[1],i=[7ff]}]
> >>
> >>
> >> Standby daemons:
> >>
> >> [mds.c{-1:11704322} state up:standby seq 1 addr [v2:
> >> 10.7.1.117:6848/84247504,v1:10.7.1.117:6849/84247504] compat
> >> {c=[1],r=[1],i=[7ff]}]
> >>
> >> чт, 21 нояб. 2024 г. в 11:36, Eugen Block <eblock@xxxxxx>:
> >>
> >>> I'm not aware of any hard limit for the number of Filesystems, but
> >>> that doesn't really mean very much. IIRC, last week during a Clyso
> >>> talk at Eventbrite I heard someone say that they deployed around 200
> >>> Filesystems or so, I don't remember if it was a production environment
> >>> or just a lab environment. I assume that you would probably be limited
> >>> by the number of OSDs/PGs rather than by the number of Filesystems,
> >>> 200 Filesystems require at least 400 pools. But maybe someone else has
> >>> more experience in scaling CephFS that way. What we did was to scale
> >>> the number of active MDS daemons for one CephFS. I believe in the end
> >>> the customer had 48 MDS daemons on three MDS servers, 16 of them were
> >>> active with directory pinning, at that time they had 16 standby-replay
> >>> and 16 standby daemons. But it turned out that standby-replay didn't
> >>> help their use case, so we disabled standby-replay.
> >>>
> >>> Can you show the entire 'ceph fs status' output? Any maybe also 'ceph
> >>> fs dump'?
> >>>
> >>> Zitat von Александр Руденко <a.rudikk@xxxxxxxxx>:
> >>>
> >>>>>
> >>>>> Just for testing purposes, have you tried pinning rank 1 to some
> other
> >>>>> directory? Does it still break the CephFS if you stop it?
> >>>>
> >>>>
> >>>> Yes, nothing changed.
> >>>>
> >>>> It's no problem that FS hangs when one of the ranks goes down, we will
> >>> have
> >>>> standby-reply for all ranks. I don't like that rank which is not
> pinned
> >>> to
> >>>> some dir handled some io of this dir or from clients which work with
> this
> >>>> dir.
> >>>> I mean that I can't robustly and fully separate client IO by ranks.
> >>>>
> >>>> Would it be an option to rather use multiple Filesystems instead of
> >>>>> multi-active for one CephFS?
> >>>>
> >>>>
> >>>> Yes, it's an option. But it is much more complicated in our case.
> Btw, do
> >>>> you know how many different FS can be created in one cluster? Maybe
> you
> >>>> know some potential problems with 100-200 FSs in one cluster?
> >>>>
> >>>> ср, 20 нояб. 2024 г. в 17:50, Eugen Block <eblock@xxxxxx>:
> >>>>
> >>>>> Ah, I misunderstood, I thought you wanted an even distribution across
> >>>>> both ranks.
> >>>>> Just for testing purposes, have you tried pinning rank 1 to some
> other
> >>>>> directory? Does it still break the CephFS if you stop it? I'm not
> sure
> >>>>> if you can prevent rank 1 from participating, I haven't looked into
> >>>>> all the configs in quite a while. Would it be an option to rather use
> >>>>> multiple Filesystems instead of multi-active for one CephFS?
> >>>>>
> >>>>> Zitat von Александр Руденко <a.rudikk@xxxxxxxxx>:
> >>>>>
> >>>>> > No it's not a typo. It's misleading example)
> >>>>> >
> >>>>> > dir1 and dir2 are pinned to rank 0, but FS and dir1,dir2 can't work
> >>>>> without
> >>>>> > rank 1.
> >>>>> > rank 1 is used for something when I work with this dirs.
> >>>>> >
> >>>>> > ceph 16.2.13, metadata balancer and policy based balancing not
> used.
> >>>>> >
> >>>>> > ср, 20 нояб. 2024 г. в 16:33, Eugen Block <eblock@xxxxxx>:
> >>>>> >
> >>>>> >> Hi,
> >>>>> >>
> >>>>> >> > After pinning:
> >>>>> >> > setfattr -n ceph.dir.pin -v 0 /fs-mountpoint/dir1
> >>>>> >> > setfattr -n ceph.dir.pin -v 0 /fs-mountpoint/dir2
> >>>>> >>
> >>>>> >> is this a typo? If not, you did pin both directories to the same
> >>> rank.
> >>>>> >>
> >>>>> >> Zitat von Александр Руденко <a.rudikk@xxxxxxxxx>:
> >>>>> >>
> >>>>> >> > Hi,
> >>>>> >> >
> >>>>> >> > I try to distribute all top level dirs in CephFS by different
> MDS
> >>>>> ranks.
> >>>>> >> > I have two active MDS with rank *0* and *1 *and I have 2 top
> dirs
> >>> like
> >>>>> >> > */dir1* and* /dir2*.
> >>>>> >> >
> >>>>> >> > After pinning:
> >>>>> >> > setfattr -n ceph.dir.pin -v 0 /fs-mountpoint/dir1
> >>>>> >> > setfattr -n ceph.dir.pin -v 0 /fs-mountpoint/dir2
> >>>>> >> >
> >>>>> >> > I can see next INOS and DNS distribution:
> >>>>> >> > RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS
> >>>>> >> > 0 active c Reqs: 127 /s 12.6k 12.5k 333 505
> >>>>> >> > 1 active b Reqs: 11 /s 21 24 19 1
> >>>>> >> >
> >>>>> >> > When I write to dir1 I can see a small amount on Reqs: in rank
> 1.
> >>>>> >> >
> >>>>> >> > Events in journal of MDS with rank 1:
> >>>>> >> > cephfs-journal-tool --rank=fs1:1 event get list
> >>>>> >> >
> >>>>> >> > 2024-11-20T12:24:42.045056+0300 0xc5c1cb UPDATE:
> >>>>> (scatter_writebehind)
> >>>>> >> > A2037D53
> >>>>> >> > 2024-11-20T12:24:46.935934+0300 0xc5c629 SESSION: ()
> >>>>> >> > 2024-11-20T12:24:47.192012+0300 0xc5c7cd UPDATE: (lock inest
> >>>>> accounted
> >>>>> >> > scatter stat update)
> >>>>> >> > 2024-11-20T12:24:47.904717+0300 0xc5ca0b SESSION: ()
> >>>>> >> > 2024-11-20T12:26:46.912719+0300 0xc5ca98 SESSION: ()
> >>>>> >> > 2024-11-20T12:26:47.910806+0300 0xc5cc3c SESSION: ()
> >>>>> >> > 2024-11-20T12:27:35.746239+0300 0xc5ccc9 SESSION: ()
> >>>>> >> > 2024-11-20T12:28:46.923812+0300 0xc5ce63 SESSION: ()
> >>>>> >> > 2024-11-20T12:28:47.903066+0300 0xc5d007 SESSION: ()
> >>>>> >> > 2024-11-20T12:29:08.063326+0300 0xc5d094 EXPORT: ()
> >>>>> >> > di1/A2037D53
> >>>>> >> > 2024-11-20T12:30:46.909621+0300 0xc5d96f SESSION: ()
> >>>>> >> > 2024-11-20T12:30:47.908050+0300 0xc5db13 SESSION: ()
> >>>>> >> > 2024-11-20T12:32:46.907649+0300 0xc5dba0 SESSION: ()
> >>>>> >> > 2024-11-20T12:32:47.905962+0300 0xc5dd44 SESSION: ()
> >>>>> >> > 2024-11-20T12:34:44.349348+0300 0xc5ddd1 SESSIONS: ()
> >>>>> >> >
> >>>>> >> > But the main problem, when I stop MDS rank 1 (without any kind
> of
> >>>>> >> standby)
> >>>>> >> > - FS hangs for all actions.
> >>>>> >> > Is this correct? Is it possible to completely exclude rank 1
> from
> >>>>> >> > processing dir1 and not stop io when rank 1 goes down?
> >>>>> >> > _______________________________________________
> >>>>> >> > ceph-users mailing list -- ceph-users@xxxxxxx
> >>>>> >> > To unsubscribe send an email to ceph-users-leave@xxxxxxx
> >>>>> >>
> >>>>> >>
> >>>>> >> _______________________________________________
> >>>>> >> ceph-users mailing list -- ceph-users@xxxxxxx
> >>>>> >> To unsubscribe send an email to ceph-users-leave@xxxxxxx
> >>>>> >>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>
> >>>
> >>>
> >>>
>
>
>
>
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