any way to limit yum's memory/cpu usage?

[joshb]

I'm able to install small packages via yum, but it looks to me like I'm having problems installing larger ones. It looks like the yum process is running out of memory, as I keep getting 'memory alloc' issues:

[root@vps ~]# yum install qmail-scanner

Unable to find pid
Gathering header information file(s) from server(s)
Server: CentOS-4 - Addons
Server: Atomic Rocket Turtle - 4 - Atomic PSA-Compatible RPMS
Server: CentOS-4 - Base
Server: CentOS-4 - Extras
Server: CentOS-4 - Updates
Finding updated packages
Downloading needed headers
Resolving dependencies
memory alloc (95456 bytes) returned NULL.

My poor little VPS is only a 192MB RAM plan, burstable to 1GB. Idling just before I run the yum command, I'm using 152MB of RAM. While yum is running, the memory usage peaks at about 256MB, just before the process errors out.

Am I simply out of luck? How can I work around this issue? Do I need to submit a support ticket and let support install the packages for me?

Thanks for any advice,

Josh

[JPC-Masood]

Support will not be able to overcome the RAM shortage either (unless they increase it temporarily to let yum eat more RAM). One solution would be to temporarily stop some services to reduce memory usage.

[joshb]

Alright, so what does 'burstable' actually mean? I know that I'm guaranteed 192MB of RAM, with bursts up to 1GB. How long is a burst? If I'm only going to need that amount for < 1min, for a max of a few times a month, does that fall under the burst limit? Or is that dependent on the rest of the VPS accounts on the server and how much they're using at that moment?

[jason]

It is, to my knowledge, dependent on the other instances on the server. I likened it once before to the large study tables often found in libraries. If you're alone at the table you can use all of the space to spread out, but if someone else comes in and starts using some of that space the amount available to you decreases by whatever the other person needs. If a third person sits down your usable space is further reduced, but if the second person leaves you can then "burst" into the space she previously used.

Make sense?

--Jason

[joshb]

That makes sense to me. It's also how I understood it to work, I just wanted to make sure.

Since I was only able to burst into 256MB of RAM before my process died, I assume that means the rest of the server was busy. Hmm... maybe I can try my updates in the middle of the night (EST), in the hopes that the rest of the accounts are US-based too, and won't be quite so busy then.

[joshb]

I was able to complete the desired installation via yum, by stopping the httpd, mysqld and spamd services. One thing I couldn't find was how to stop the httpsd service. That would be the last of the larger memory using programs I had running (already had disabled mailman). How would I stop it? All the references I found online pointed to /etc/rc.d/init.d/httpsd, which isn't there on my VPS.

[Smithjp]

httpsd is the webserver that Plesk uses. You can stop it by stopping the Plesk service "psa" i.e /etc/init.d/psa stopall.

[joshb]

Also, for the benefit of anyone else reading this later on, the service command is awfully helpful for starting, stopping and restarting the system services like so

service httpd start/stop/restart

If you're having trouble finding the service command (as I was), it's in /sbin. On my VPS, /sbin wasn't in my path by default.

[st1905]

Strange thing is i`ve installed so many things with yum and i`m with the same plan like you (192mbram), i`ve never experienced memory allocation problems but after some large upgrades i`ve touched the qos limits. After the update or install with yum everything got back to normal. I`ve installed so many things without any error. Maybe you`ve innodb enabled in your mysql config which takes huge 10mb memory.

You can always disable it in /etc/my.cnf with the following

skip-innodb

[joshb]

Strange thing is i`ve installed so many things with yum and i`m with the same plan like you (192mbram), i`ve never experienced memory allocation problems but after some large upgrades i`ve touched the qos limits. After the update or install with yum everything got back to normal. I`ve installed so many things without any error. Maybe you`ve innodb enabled in your mysql config which takes huge 10mb memory.

You can always disable it in /etc/my.cnf with the following

skip-innodb

Thanks, I'll try that.

My problems may also be as result of the change discussed in this thread. Seems like "bursting" is really "memory that looks like it's available, but any apps that dip into it will be killed." At least, that's what I observed. Memory usage would go up to about 256MB, then the yum process would be killed. It's possible that your significant usage of yum was before the UBC-> SLM change.

[Ron]

Interesting discussion on WHT:
http://www.webhostingtalk.com/showthread.php?t=524222

[joshb]

Strange thing is i`ve installed so many things with yum and i`m with the same plan like you (192mbram), i`ve never experienced memory allocation problems but after some large upgrades i`ve touched the qos limits. After the update or install with yum everything got back to normal. I`ve installed so many things without any error. Maybe you`ve innodb enabled in your mysql config which takes huge 10mb memory.

You can always disable it in /etc/my.cnf with the following

skip-innodb

Well, I tried that, and Plesk most definitely did not like it. I did the skip-innodb, as well as commenting out all the set-variable calls relating to innodb. I was still able to log in to Plesk, but a good portion of the functionality was not working.

Turned those things back on, restart mysqld, and everything's back to normal.

[thisisit3]

I believe the VPS systems offered by Jag are using the UBC method of memory management.

I've had problems with memory limits and had the same issues with burstable memory, it plainly didn't work. My memory usage would use about ~128mb of bustable memory and then they would die pretty quickly.

Reading about the SLM method of memory management, i believe that it gives much better results as reported by users of other hosting services.

Maybe Jag could take a closer look at SLM? Since memory is the biggest problem for VPS systems because its just too little.