> ps: When we first met this issue, restarting the mds could cure that. (but that was ceph 0.94.1).
Is this still working?
Since you're using 0.94.9, bug(#12551) you mentioned was fixed.
Can you do the followings to see object appear to you as ZERO size is
actually there:
# rados -p ${cache pool} ls
# rados -p ${cache pool} get ${object} /tmp/file
# ls -l /tmp/file
------------------ Original ------------------
From: "Shinobu Kinjo"<skinjo@xxxxxxxxxx>;
Date: Tue, Dec 13, 2016 06:21 PM
To: "JiaJia Zhong"<zhongjiajia@xxxxxxxxxxxx>;
Cc: "CEPH list"<ceph-users@xxxxxxxxxxxxxx>; "ukernel"<ukernel@xxxxxxxxx>;
Subject: Re: can cache-mode be set to readproxy for tier
cachewith ceph 0.94.9 ?
On Tue, Dec 13, 2016 at 4:38 PM, JiaJia Zhong <zhongjiajia@xxxxxxxxxxxx> wrote:
>
> hi cephers:
> we are using ceph hammer 0.94.9, yes, It's not the latest ( jewel),
> with some ssd osds for tiering, cache-mode is set to readproxy, everything seems to be as expected,
> but when reading some small files from cephfs, we got 0 bytes.
Would you be able to share:
#1 How small is actual data?
#2 Is the symptom reproduceable with same size of different data?
#3 can you share your ceph.conf(ceph --show-config)?
>
>
> I did some search and got the below link,
> http://ceph-users.ceph.narkive.com/g4wcB8ED/cephfs-with-cache-tiering-reading-files-are-filled-with-0s
> that's almost the same as what we are suffering from except the cache-mode in the link is writeback, ours is readproxy.
>
> that bug shall have been FIXED in 0.94.9 (http://tracker.ceph.com/issues/12551)
> but we still can encounter with that occasionally ：(
>
> enviroment:
> - ceph: 0.94.9
> - kernel client: 4.2.0-36-generic ( ubuntu 14.04 )
> - any others needed ?
>
> Question:
> 1. does readproxy mode work on ceph0.94.9 ? since there are only writeback and readonly in the document for hammer.
> 2. any one with (Jewel or Hammer) met the same issue ?
>
>
> loop Yan, Zheng
> Quote from the link for convince.
> """
> Hi,
>
> I am experiencing an issue with CephFS with cache tiering where the kernel
> clients are reading files filled entirely with 0s.
>
> The setup:
> ceph 0.94.3
> create cephfs_metadata replicated pool
> create cephfs_data replicated pool
> cephfs was created on the above two pools, populated with files, then:
> create cephfs_ssd_cache replicated pool,
> then adding the tiers:
> ceph osd tier add cephfs_data cephfs_ssd_cache
> ceph osd tier cache-mode cephfs_ssd_cache writeback
> ceph osd tier set-overlay cephfs_data cephfs_ssd_cache
>
> While the cephfs_ssd_cache pool is empty, multiple kernel clients on
> different hosts open the same file (the size of the file is small, <10k) at
> approximately the same time. A number of the clients from the OS level see
> the entire file being empty. I can do a rados -p {cache pool} ls for the
> list of files cached, and do a rados -p {cache pool} get {object} /tmp/file
> and see the complete contents of the file.
> I can repeat this by setting cache-mode to forward, rados -p {cache pool}
> cache-flush-evict-all, checking no more objects in cache with rados -p
> {cache pool} ls, resetting cache-mode to writeback with an empty pool, and
> doing the multiple same file opens.
>
> Has anyone seen this issue? It seems like what may be a race condition
> where the object is not yet completely loaded into the cache pool so the
> cache pool serves out an incomplete object.
> If anyone can shed some light or any suggestions to help debug this issue,
> that would be very helpful.
>
> Thanks,
> Arthur"""
>
>
>
> _______________________________________________
> ceph-users mailing list
> ceph-users@xxxxxxxxxxxxxx
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>
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