[SERVER-442] durability: sync files to disk every minute, configurable Created: 27/Nov/09  Updated: 12/Jul/16  Resolved: 27/Nov/09

Status: Closed
Project: Core Server
Component/s: Stability
Affects Version/s: None
Fix Version/s: 1.1.4

Type: New Feature Priority: Major - P3
Reporter: Eliot Horowitz (Inactive) Assignee: Eliot Horowitz (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Participants:

 Comments   
Comment by Eliot Horowitz (Inactive) [ 13/Dec/09 ]

This is not meant to solve durability
there are certain cases where this is very helpful though. For example when running on a laptop that runs out of battery life.
Repair still has to be run of course.

Comment by Ivan Voras [ 13/Dec/09 ]

If there are any dynamic data structures in the mmaped region (e.g. trees, hashes, etc), this change will not help durability at all if the mmaped region is left to be partially synced on-demand by the operating system's VM system between fsync()s (this is very easy to see if you think about it). And there is no way to create an always-synchronous mechanism of storage with mmap().

In terms of durability, calling fsync() every minute in these circumstances is a no-op.

Comment by auto [ 27/Nov/09 ]

Author:

{'name': 'Eliot Horowitz', 'email': 'eliot@10gen.com'}

Message: durability: added occasinal file sync
default: sync every 60 seconds, confiruable with syncdelay
SERVER-442
http://github.com/mongodb/mongo/commit/c44bff08fd95616302a73e92b48b2853c1fd948d

Comment by Eliot Horowitz (Inactive) [ 27/Nov/09 ]

defaults to every minute.
configurable with --syncdelay

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