Support #23677
closed
rbd mirror: is there a method to calculate data size that have not been mirror to non-primary image?
Added by liuzhong chen about 6 years ago.
Updated about 4 years ago.
Description
When I use rbd mirror between two cluster, is there a method to calculate data size that have not been mirror to non-primary image?
Now I have find the info below.But I don't know if I can calculate the data size with these info.
rbd mirror image status poolclz/rbdclz
rbdclz:
global_id: 3bf9e3cf-353f-4afb-b54a-08b3734ec841
state: up+replaying
description: replaying, master_position=[object_number=3, tag_tid=5, entry_tid=3467], mirror_position=[object_number=3, tag_tid=5, entry_tid=31], entries_behind_master=3436
last_update: 2018-04-12 20:17:37
Thank you!
ceph version:12.2.4
@Jason Borden Dillaman,I have tried some method but can't.Do you have any advise.Thank you!
@liuzhong chen: There is no such support right now. The "entries_behind_master" is just a simple counter of the number of known journal entries that remain that is extracted from metadata. There is no associated entry size in that metadata so the only way to get a real number would be to read the entire journal (which is what occurs one record at a time during replay). The best you could attempt would be to gather some statistics about average entry size and the average number of entries committed per second to compute an estimate remaining size and backlog time.
We have a ticket in our backlog to cover this improvement [1] at some point in the future.
[1] https://trello.com/c/FhQ29aQ9
@Jason Borden Dillaman, OK,understanded.Thank you very much.
Another quetion, this issue [[http://tracker.ceph.com/issues/23516]].I read the cord of Replayer.cc.if entries_behind_master is less 32
IO,it would not be flushed.It also means that these entry will be not replayed for non-primary image which lead the non-primary image is not exactly the same as primary image.Am I right?
Thank you!
liuzhong chen wrote:
@Jason Borden Dillaman, OK,understanded.Thank you very much.
Another quetion, this issue http://tracker.ceph.com/issues/23516.I read the code of Replayer.cc.if entries_behind_master is less 32
IO,it would not be flushed.It also means that these entry will be not replayed for non-primary image which lead the non-primary image is not exactly the same as primary image.Am I right?
Thank you!
liuzhong chen wrote:
IO,it would not be flushed.It also means that these entry will be not replayed for non-primary image which lead the non-primary image is not exactly the same as primary image.Am I right?
No, that's not correct. Since rbd-mirror doesn't use a cache, it is safely replayed and stored in the non-primary image. The issue is that the commit position isn't updated, which affects the status display.
this support can be close if needed.
- Status changed from New to Closed
Also available in: Atom
PDF