linux-kernel - Re: very poor ext3 write performance on big filesystems?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Sat, 01 Mar 2008 15:04:29 -0500
From:	Bill Davidsen <davidsen@....com>
To:	Andreas Dilger <adilger@....COM>
CC:	Tomasz Chmielewski <mangoo@...g.org>, Theodore Tso <tytso@....edu>,
	Andi Kleen <andi@...stfloor.org>,
	LKML <linux-fsdevel@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>, linux-raid@...r.kernel.org
Subject: Re: very poor ext3 write performance on big filesystems?

Andreas Dilger wrote:
> I'm CCing the linux-raid mailing list, since I suspect they will be
> interested in this result.
>
> I would suspect that the "journal guided RAID recovery" mechanism
> developed by U.Wisconsin may significantly benefit this workload
> because the filesystem journal is already recording all of these
> block numbers and the MD bitmap mechanism is pure overhead.
>   

Thanks for sharing these numbers. I think use of a bitmap is one of 
those things which people have to configure to match their use, 
certainly using a larger bitmap seems to reduce the delays, using an 
external bitmap certainly help, especially on an SSD. But on a large 
array, without a bitmap, performance can be compromised for hours during 
recovery, so the administrator must decide if normal case performance is 
more important than worst case performance.

-- 
Bill Davidsen <davidsen@....com>
  "Woe unto the statesman who makes war without a reason that will still
  be valid when the war is over..." Otto von Bismark 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/