[LU-10018] MDT as a statfs proxy Created: 22/Sep/17  Updated: 05/Jun/19  Resolved: 01/Sep/18

Status: Resolved
Project: Lustre
Component/s: None
Affects Version/s: None
Fix Version/s: Lustre 2.12.0

Type: Improvement Priority: Minor
Reporter: Alex Zhuravlev Assignee: Alex Zhuravlev
Resolution: Fixed Votes: 0
Labels: OSJ

Issue Links:
Blocker
is blocking LU-7236 connections on demand Resolved
Related
is related to LU-11375 Client 2.10 fails to mount Server 2.1... Resolved
is related to LU-7770 conf-sanity test_50b: Error: 'lazysta... Resolved
is related to LU-11721 "lfs df -i" prints used blocks percen... Resolved
is related to LU-7880 add performance statistics to obd_statfs Open
is related to LU-7233 parallelize lmv_statfs() implementation Resolved
is related to LU-9555 "df /path/to/project" should return p... Resolved
Rank (Obsolete): 9223372036854775807

 Description   

given MDT updates statfs data from all OSTs every second it can provide data to the clients. this can be useful for idling connections feature as we won't need to connect to OST for a single OST_STATFS RPC. this can also make df less expensive in terms of RPC and faster.

 Comments   
Comment by Andreas Dilger [ 19/Oct/17 ]

Not sure why this wasn't added automatically:

https://review.whamcloud.com/29136

LU-10018 protocol: MDT as a statfs proxy
MDT can act as a proxy for statfs data. this should
make df faster (RTT vs RTT*(#MDTs+11)) and enable
idling connections so that clients don't connect to
each OST just to report statfs data. the protocol
has been changing slightly to let MDT differentiate
self and aggregated statfs.
also, obd_statfs has got a new field "granted" where
OST reports how much space has been granted to the
requesting MDT so that space can be added to available
space.

TODO:
- clients to use different MDTs to balance load

Change-Id: I59e03cb5abf809ae8820f874ec51dd2b74e1806c
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Comment by Gerrit Updater [ 01/Sep/18 ]

Oleg Drokin (green@whamcloud.com) merged in patch https://review.whamcloud.com/29136/
Subject: LU-10018 protocol: MDT as a statfs proxy
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: b500d5193360711a6c6b07497f34e61cc590cf19

Comment by Peter Jones [ 01/Sep/18 ]

Landed for 2.12

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