Re: Disk performance issue - CVS on AIX

[Bill V Vickery]

Very helpful advice sir.  Further investigation yesterday afternoon 
revealed that the main respository is set in a subdir off /usr, with /tmp 
getting heavy usage as you suggest as a temporary storage area.  Bottom 
line....both are still on a pair of mirrored SCSI drives.  It isn't just 
ssh that is slow...it is all commands.  For example, on the machine most 
recently impacted it took 45 minutes just for a shutdown command to 
complete.  We'll look at moving the repository and the temporary storage 
area out to more appropriate disk.

Kindest Regards,

Bill Vickery
RITS/UNIX Team lead
Office: (801) 333-5818

To provide feedback regarding RITS service, click here: 
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iain.mees@ba.com 
09/26/2008 03:01 AM


To
"Bill V Vickery" <wvvicke@regence.com>
cc
bug-cvs@nongnu.org, bug-cvs-bounces+iain.mees=ba.com@nongnu.org
Subject
Re: Disk performance issue - CVS on AIX







Bill, 

We run a massive CVS repository here at British Airways on AIX5.3. I have 
customised it significantly and it is running in a chroot jail rather than 
native for security reasons. 

Running from /tmp is not something I have ever heard of, or would 
recommend (/tmp is for temporary files, not applications). CVS is not 
really CPU bound, but can be rather i/o bound when it comes to checking a 
number of items in/out. It also tends to use /tmp frequently as a 
temporary storage area. As your repository is also in /tmp I would be 
inclined to say that your i/o is out performing your disk capability. 

If I remember correctly, you can change the cvs temp area (during compile 
I think). but your most sensible thing would be to move your repository to 
a proper filesystem, preferably on a different physical disk. 

With regard to SSH being slow... If you are running OpenSSH, then try 
making it running it as a daemon rather than via inetd. That way it 
doesn't need to start for every connection as its already in storage. 

Hope this helps 

Iain 



"Bill V Vickery" <wvvicke@regence.com> 
Sent by: bug-cvs-bounces+iain.mees=ba.com@nongnu.org 
26/09/2008 05:15 


To
bug-cvs@nongnu.org 
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Subject
Disk performance issue - CVS on AIX








Anyone aware of a disk performance issue with CVS in AIX 5.2, where 
repository is located in /tmp and generating sufficient I/O load that it 
brings rootvg disks to 100%, with essentially zero throughput.  System 
becomes unresponsive taking several minutes just to open a new ssh 
session.  Any comments/advice would be appreciated.

Kindest Regards,

Bill Vickery
RITS/UNIX Team lead
Office: (801) 333-5818

To provide feedback regarding RITS service, click here: 
https://www.surveymonkey.com/s.aspx?sm=sZVET5w4IdkhFwVArVPO4g_3d_3d
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