Bug 1531679

Summary:	mds memory tracking of cache is imprecise by a constant factor
Product:	[Red Hat Storage] Red Hat Ceph Storage	Reporter:	Patrick Donnelly <pdonnell>
Component:	CephFS	Assignee:	Patrick Donnelly <pdonnell>
Status:	CLOSED ERRATA	QA Contact:	Ramakrishnan Periyasamy <rperiyas>
Severity:	high	Docs Contact:	Aron Gunn <agunn>
Priority:	high
Version:	3.0	CC:	agunn, ceph-eng-bugs, ceph-qe-bugs, john.spray, pdonnell, rperiyas, vakulkar
Target Milestone:	z3
Target Release:	3.0
Hardware:	All
OS:	All
Whiteboard:
Fixed In Version:	RHEL: ceph-12.2.4-10.el7cp Ubuntu: ceph_12.2.4-14redhat1xenial	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-05-15 18:20:29 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Patrick Donnelly 2018-01-05 19:16:16 UTC

Description of problem:


Version-Release number of selected component (if applicable):

3.0

How reproducible:

100%

Steps to Reproduce:
0. Use an MDS with a very large cache (64GB+) to easily observe the problem. Set mds_cache_memory_limit to the desired maximum size.
1. Fill MDS cache by accessing millions of files

Actual results:

Observe the MDS uses much more than 64GB in RAM.

Expected results:

It should only be off mds_cache_memory_limit by a small factor.

Comment 3 Patrick Donnelly 2018-01-05 19:25:53 UTC

Documentation for issue: http://tracker.ceph.com/issues/22599

Comment 16 errata-xmlrpc 2018-05-15 18:20:29 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:1563