linux-kernel - How to track down abysmal performance ata - raid1 - crypto - vg/lv

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Wed, 4 Aug 2010 09:35:46 +0200
From:	Dominik Brodowski <linux@...inikbrodowski.net>
To:	linux-raid@...r.kernel.org, xfs@....sgi.com,
	linux-kernel@...r.kernel.org
Subject: How to track down abysmal performance ata - raid1 - crypto - vg/lv
 - xfs

Hey,

on a production system I run kernel 2.6.35 and

	XFS	(rw,relatime,nobarrier)

on a

	lvdevice of a vgroup 

consisting of five

	dm-crypt devices (cryptsetup -c aes-lrw-benbi -s 384 create)

, each of which runs on a

	md-raid1 device (mdadm --create --level=raid1 --raid-devices=2)

on two

	750 GB ATA devices.


The read performance is abysmal. The ata devices can be ruled out, as hdparm
resulted in acceptable performance:
> Timing cached reads:   9444 MB in  2.00 seconds = 4733.59 MB/sec
> Timing buffered disk reads:  298 MB in  3.02 seconds =  98.73 MB/sec

How can I best track down the cause of the performance problem, 
a) without rebooting too often, and
b) without breaking up the setup specified above (production system)?

Any ideas? perf(1)? iostat(1)?

Thanks & best,

	Dominik
--
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/