Hi,
Today while debugging something we had a few questions that might lead
to improving the cephfs forward scrub docs:
https://docs.ceph.com/en/latest/cephfs/scrub/
tldr:
1. Should we document which sorts of issues that the forward scrub is
able to fix?
2. Can we make it more visible (in docs) that scrubbing is not
supported with multi-mds?
3. Isn't the new `ceph -s` scrub task status misleading with multi-mds?
Details here:
1) We found a CephFS directory with a number of zero sized files:
# ls -l
...
-rw-r--r-- 1 1001890000 1001890000 0 Nov 3 11:58
upload_fc501199e3e7abe6b574101cf34aeefb.png
-rw-r--r-- 1 1001890000 1001890000 0 Nov 3 12:23
upload_fce4f55348185fefa0abdd8d11095ba8.gif
-rw-r--r-- 1 1001890000 1001890000 0 Nov 3 11:54
upload_fd95b8358851f0dac22fb775046a6163.png
...
The user claims that those files were non-zero sized last week. The
sequence of zero sized files includes *all* files written between Nov
2 and 9.
The user claims that his client was running out of memory, but this is
now fixed. So I suspect that his ceph client (kernel
3.10.0-1127.19.1.el7.x86_64) was not behaving well.
Anyway, I noticed that even though the dentries list 0 bytes, the
underlying rados objects have data, and the data looks good. E.g.
# rados get -p cephfs_data 200212e68b5.00000000 --namespace=xxx
200212e68b5.00000000
# file 200212e68b5.00000000
200212e68b5.00000000: PNG image data, 960 x 815, 8-bit/color RGBA,
non-interlaced
So I managed to recover the files doing something like this (using an
input file mapping inode to filename) [see PS 0].
But I'm wondering if a forward scrub is able to fix this sort of
problem directly?
Should we document which sorts of issues that the forward scrub is able to fix?
I anyway tried to scrub it, which led to:
# ceph tell mds.cephflax-mds-xxx scrub start /volumes/_nogroup/xxx
recursive repair
Scrub is not currently supported for multiple active MDS. Please
reduce max_mds to 1 and then scrub.
So ...
2) Shouldn't we update the doc to mention loud and clear that scrub is
not currently supported for multiple active MDS?
3) I was somehow surprised by this, because I had thought that the new
`ceph -s` multi-mds scrub status implied that multi-mds scrubbing was
now working:
task status:
scrub status:
mds.x: idle
mds.y: idle
mds.z: idle
Is it worth reporting this task status for cephfs if we can't even scrub them?
Thanks!!
Dan
[0]
mkdir -p recovered
while read -r a b; do
for i in {0..9}
do
echo "rados stat --cluster=flax --pool=cephfs_data
--namespace=xxx" $(printf "%x" $a).0000000$i "&&" "rados get
--cluster=flax --pool=cephfs_data --namespace=xxx" $(printf "%x"
$a).0000000$i $(printf "%x" $a).0000000$i
done
echo cat $(printf "%x" $a).* ">" $(printf "%x" $a)
echo mv $(printf "%x" $a) recovered/$b
done < inones_fnames.txt
Hi Patrick,
Any updates? Looking forward to your reply :D
On Thu, Dec 17, 2020 at 11:39 AM Patrick Donnelly <pdonnell(a)redhat.com> wrote:
>
> On Wed, Dec 16, 2020 at 5:46 PM Alex Taylor <alexu4993(a)gmail.com> wrote:
> >
> > Hi Cephers,
> >
> > I'm using VSCode remote development with a docker server. It worked OK
> > but fails to start the debugger after /root mounted by ceph-fuse. The
> > log shows that the binary passes access X_OK check but cannot be
> > actually executed. see:
> >
> > ```
> > strace_log: access("/root/.vscode-server/extensions/ms-vscode.cpptools-1.1.3/debugAdapters/OpenDebugAD7",
> > X_OK) = 0
> >
> > root@develop:~# ls -alh
> > .vscode-server/extensions/ms-vscode.cpptools-1.1.3/debugAdapters/OpenDebugAD7
> > -rw-r--r-- 1 root root 978 Dec 10 13:06
> > .vscode-server/extensions/ms-vscode.cpptools-1.1.3/debugAdapters/OpenDebugAD7
> > ```
> >
> > I also test the access syscall on ext4, xfs and even cephfs kernel
> > client, all of them return -EACCES, which is expected (the extension
> > will then explicitly call chmod +x).
> >
> > After some digging in the code, I found it is probably caused by
> > https://github.com/ceph/ceph/blob/master/src/client/Client.cc#L5549-L5550.
> > So here come two questions:
> > 1. Is this a bug or is there any concern I missed?
>
> I tried reproducing it with the master branch and could not. It might
> be due to an older fuse/ceph. I suggest you upgrade!
>
I tried the master(332a188d9b3c4eb5c5ad2720b7299913c5a772ee) as well
and the issue still exists. My test program is:
```
#include <stdio.h>
#include <unistd.h>
int main() {
int r;
const char path[] = "test";
r = access(path, F_OK);
printf("file exists: %d\n", r);
r = access(path, X_OK);
printf("file executable: %d\n", r);
return 0;
}
```
And the test result:
```
# local filesystem: ext4
root@f626800a6e85:~# ls -l test
-rw-r--r-- 1 root root 6 Dec 19 06:13 test
root@f626800a6e85:~# ./a.out
file exists: 0
file executable: -1
root@f626800a6e85:~# findmnt -t fuse.ceph-fuse
TARGET SOURCE FSTYPE OPTIONS
/root/mnt ceph-fuse fuse.ceph-fuse
rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other
root@f626800a6e85:~# cd mnt
# ceph-fuse
root@f626800a6e85:~/mnt# ls -l test
-rw-r--r-- 1 root root 6 Dec 19 06:10 test
root@f626800a6e85:~/mnt# ./a.out
file exists: 0
file executable: 0
root@f626800a6e85:~/mnt# ./test
bash: ./test: Permission denied
```
Again, ceph-fuse says file `test` is executable but in fact it can't
be executed.
The kernel version I'm testing on is:
```
root@f626800a6e85:~/mnt# uname -ar
Linux f626800a6e85 4.9.0-7-amd64 #1 SMP Debian 4.9.110-1 (2018-07-05)
x86_64 GNU/Linux
```
Please try the program above and make sure you're running it as root
user, thank you. And if the reproduction still fails, please let me
know the kernel version.
> > 2. It works again with fuse_default_permissions=true, any drawbacks if
> > this option is set?
>
> Correctness (ironically, for you) and performance.
>
> --
> Patrick Donnelly, Ph.D.
> He / Him / His
> Principal Software Engineer
> Red Hat Sunnyvale, CA
> GPG: 19F28A586F808C2402351B93C3301A3E258DD79D
>
Hi,
There is a default limit of 1TiB for the max_file_size in CephFS. I altered that to 2TiB, but I now got a request for storing a file up to 7TiB.
I'd expect the limit to be there for a reason, but what is the risk of setting that value to say 10TiB?
--
Mark Schouten <mark(a)tuxis.nl>
Tuxis, Ede, https://www.tuxis.nl
T: +31 318 200208
Hi all,
We have a few subdirs with an rctime in the future.
# getfattr -n ceph.dir.rctime session
# file: session
ceph.dir.rctime="2576387188.090"
I can't find any subdir or item in that directory with that rctime, so
I presume that there was previously a file and that rctime cannot go
backwards [1]
Is there any way to fix these rctimes so they show the latest ctime of
the subtree?
Also -- are we still relying on the client clock to set the rctime /
ctime of a file? Would it make sense to limit ctime/rctime for any
update to the current time on the MDS ?
Best Regards,
Dan
[1] https://github.com/ceph/ceph/pull/24023/commits/920ef964311a61fcc6c0d6671b7…
I have a cephfs secondary (non-root) data pool with unfound and degraded
objects that I have not been able to recover[1]. I created an
additional data pool and used "setfattr -n ceph.dir.layout.pool' and a
very long rsync to move the files off of the degraded pool and onto the
new pool. This has completed, and using find + 'getfattr -n
ceph.file.layout.pool', I verified that no files are using the old pool
anymore. No ceph.dir.layout.pool attributes point to the old pool either.
However, the old pool still reports that there are objects in the old
pool, likely the same ones that were unfound/degraded from before:
https://pastebin.com/qzVA7eZr
Based on a old message from the mailing list[2], I checked the MDS for
stray objects (ceph daemon mds.ceph4 dump cache file.txt ; grep -i stray
file.txt) and found 36 stray entries in the cache:
https://pastebin.com/MHkpw3DV. However, I'm not certain how to map
these stray cache objects to clients that may be accessing them.
'rados -p fs.data.archive.frames ls' shows 145 objects. Looking at the
parent of each object shows 2 strays:
for obj in $(cat rados.ls.txt) ; do echo $obj ; rados -p
fs.data.archive.frames getxattr $obj parent | strings ; done
[...]
10000020fa1.00000000
10000020fa1
stray6
10000020fbc.00000000
10000020fbc
stray6
[...]
...before getting stuck on one object for over 5 minutes (then I gave up):
1000005b1af.00000083
What can I do to make sure this pool is ready to be safely deleted from
cephfs (ceph fs rm_data_pool archive fs.data.archive.frames)?
--Mike
[1]https://lists.ceph.io/hyperkitty/list/ceph-users@ceph.io/thread/QHFOGEKXK7VDNNSKR74BA6IIMGGIXBXA/#7YQ6SSTESM5LTFVLQK3FSYFW5FDXJ5CF
[2]http://lists.ceph.com/pipermail/ceph-users-ceph.com/2015-October/005233.h…
Hi,
We see that we have 5 'remapped' PGs, but are unclear why/what to do about
it. We shifted some target ratios for the autobalancer and it resulted in
this state. When adjusting ratio, we noticed two OSDs go down, but we just
restarted the container for those OSDs with podman, and they came back up.
Here's status output:
###################
root@ceph01:~# ceph status
INFO:cephadm:Inferring fsid x
INFO:cephadm:Inferring config x
INFO:cephadm:Using recent ceph image docker.io/ceph/ceph:v15
cluster:
id: 41bb9256-c3bf-11ea-85b9-9e07b0435492
health: HEALTH_OK
services:
mon: 5 daemons, quorum ceph01,ceph04,ceph02,ceph03,ceph05 (age 2w)
mgr: ceph03.ytkuyr(active, since 2w), standbys: ceph01.aqkgbl,
ceph02.gcglcg, ceph04.smbdew, ceph05.yropto
osd: 168 osds: 168 up (since 2d), 168 in (since 2d); 5 remapped pgs
data:
pools: 3 pools, 1057 pgs
objects: 18.00M objects, 69 TiB
usage: 119 TiB used, 2.0 PiB / 2.1 PiB avail
pgs: 1056 active+clean
1 active+clean+scrubbing+deep
io:
client: 859 KiB/s rd, 212 MiB/s wr, 644 op/s rd, 391 op/s wr
root@ceph01:~#
###################
When I look at ceph pg dump, I don't see any marked as remapped:
###################
root@ceph01:~# ceph pg dump |grep remapped
INFO:cephadm:Inferring fsid x
INFO:cephadm:Inferring config x
INFO:cephadm:Using recent ceph image docker.io/ceph/ceph:v15
dumped all
root@ceph01:~#
###################
Any idea what might be going on/how to recover? All OSDs are up. Health is
'OK'. This is Ceph 15.2.4 deployed using Cephadm in containers, on Podman
2.0.3.
