My point is rbd device should support SCSI reservation, so that OCFS can take write lock while write on particular client to avoid corruption.
Thanks,
Srinivas
From: gjprabu [mailto:gjprabu@xxxxxxxxxxxx]
Sent: Monday, January 04, 2016 1:40 PM
To: Srinivasula Maram
Cc: Somnath Roy; ceph-users; Siva Sokkumuthu
Subject: RE: [ceph-users] OSD size and performance
Our cause OCFS2 is not directly interacting with SCSI. Here we have ceph Storage that is mounted to many client system using OCFS2. More ever ocfs2 support SCSI.
---- On Mon, 04 Jan 2016 12:46:48 +0530
Srinivasula Maram <Srinivasula.Maram@xxxxxxxxxxx>wrote ----
I doubt rbd driver will not support SCSI Reservation to mount the same rbd across multiple clients with OCFS ?
Generally underlying devices(here rbd) should have SCSI reservation support for cluster file system.
Thanks,
Srinivas
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx]
On Behalf Of Somnath Roy
Sent: Monday, January 04, 2016 12:29 PM
To: gjprabu
Cc: ceph-users; Siva Sokkumuthu
Subject: Re: [ceph-users] OSD size and performance
Hi Prabu,
Check the krbd version (and libceph) running in the kernel..You can try building the latest krbd source for the 7.1 kernel if this is an option for you.
As I mentioned in my earlier mail, please isolate problem the way I suggested if that seems reasonable to you.
Thanks & Regards
Somnath
From: gjprabu [mailto:gjprabu@xxxxxxxxxxxx]
Sent: Sunday, January 03, 2016 10:53 PM
To: gjprabu
Cc: Somnath Roy; ceph-users; Siva Sokkumuthu
Subject: Re: [ceph-users] OSD size and performance
Just check the below details and let us know do you need any other information.
Please check the details and help me on this issue.
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We are using RBD, please find linux and rbd versions. I agree this is related to client side issue. My though gone to backup because weekly once will take full backup not incremental at the time
we found issue once but not sure.
CentOS Linux release 7.1.1503 (Core)
ceph version 0.94.5 (9764da52395923e0b32908d83a9f7304401fee43)
id pool image snap device
1 rbd downloads - /dev/rbd1
Client server RBD mounted using ocfs2 file system.
/dev/rbd1 ocfs2 9.6T 2.6T 7.0T 27% /data/downloads
Client level cluster configuration done with 5 clients and We are using below procedure in client node.
1) rbd map downloads --pool rbd --name client.admin -m 192.168.112.192,192.168.112.193,192.168.112.194 -k /etc/ceph/ceph.client.admin.keyring
2) Formatting rbd with ocfs2
mkfs.ocfs2 -b4K -C 4K -L label -T mail -N5 /dev/rbd/rbd/downloads
3) We have do ocfs2 client level configuration and start ocfs2 service.
4) mount /dev/rbd/rbd/downloads /data/downloads
Please let me know do you need any other information.
_______________________________________________
Prabu,
I assume you are using krbd then..Could you please let us know the Linux version/flavor you are using ?
Krbd had some hang issues and supposed to be fixed with the latest versions available..Also, it could be due to OCFS2->krbd integration as well (?) ..Handling
data consistency is the responsibility of OCFS as krbd doesn’t guarantee that..So, I would suggest to do the following to root cause if your cluster is not into production.
1. Do a synthetic fio run on krbd alone (or creating a filesystem on top) and see if you can reproduce the hang
2. Try building the latest krbd or upgrade your Linux version to get a newer krbd and see if it is still happening.
<< Also we are taking backup from client, we feel that could be the reason for this hang
I assume this is regular filesystem back up ? Why do you think this could be a problem ?
I think it is a client side issue , I doubt it could be because of large OSD size..
Thanks & Regards
Somnath
From: gjprabu [mailto:gjprabu@xxxxxxxxxxxx]
Sent: Wednesday, December 30, 2015 4:29 AM
To: gjprabu
Cc: Somnath Roy; ceph-users; Siva Sokkumuthu
Subject: Re: [ceph-users] OSD size and performance
Thanks for your reply. Current setup we are having client hang issue and its hang frequently and after reboot it is working, Client used to mount with OCFS2 file system for multiple concurrent client
access for same data. Also we are taking backup from client, we feel that could be the reason for this hang.
FYI , we are using 8TB SSD drive as OSD and not seeing any problem so far. Failure domain could be a concern for bigger OSDs.
Thanks & Regards
Somnath
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx]
On Behalf Of gjprabu
Sent: Tuesday, December 29, 2015 9:38 PM
To: ceph-users
Cc: Siva Sokkumuthu
Subject: Re: [ceph-users] OSD size and performance
Anybody please clarify the below queries.
We are using ceph with 3 osd and 2 replicas. Each osd size is 13TB and current data is reached to 2.5TB (each osd). Because of this huge size do we face any problem.
CPU -- 2 CPU with multi 8 core processor.
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