4,577 reputation
11034
bio website mattdm.org
location Somerville, MA
age
visits member for 3 years, 9 months
seen 11 hours ago

I'm the Fedora Project Leader. I work for Red Hat — and for the Fedora community at large! – but my posts here are all my own.

Previously, I was a sysadmin in the Academic Computing group at Harvard School of Engineering and Applied Sciences, and before that, I made Boston University Linux.


Mar
8
comment MPM Prefork, too many apache2 process?
@yes123: sounds like a good plan. Watch for php memory limit messages in the error log.
Mar
8
comment Is it normal to get hundreds of break-in attempts per day?
@STATUS_ACCESS_DENIED: adding to hosts.deny can be problematic too, depending on what's already there and what's in hosts.allow. The iptables solution doesn't require on-the-fly munging of a text file, either. It's better and more robust all around.
Mar
8
comment Server not responding to SSH and HTTP but ping works
@yes123: In short, no. See virtualthreads.blogspot.com/2006/02/…. But, even if it were freed, you're setting yourself up for a crash when load gets high.
Mar
8
comment Server not responding to SSH and HTTP but ping works
Also, I suspect that you don't have a memory leak, but rather a PHP script which is able to consume a lot of RAM. Apache processes will expand to the maximum memory used by PHP, and not go back down. So setting MaxRequestsPerChild ridiculously low will mitigate this, but the solution is to either a) reign in your PHP app's memory consumption or b) switch to a different server architecture (using fastcgi for php).
Mar
8
comment Server not responding to SSH and HTTP but ping works
Do the math here. If you have 1500 servers, even if they're a svelte 10MB each, that's 15GB of RAM. If 190MB is a typical size for an apache process with your workload (php?), and you have 4GB of ram, ServerLimit should be no more than 21.
Mar
8
comment Server not responding to SSH and HTTP but ping works
Change your apache configuration to not start more processes than you have RAM for.
Mar
8
comment Configuring Jira to respond to requests for a specific IP address only?
@jtalarico: in that case, you're doing it wrong. :) You want apache to act as a proxy talking to tomcat as a backend, and not expose tomcat to the world. (Have tomcat bind to localhost.)
Mar
3
comment Scratch files in /tmp getting mysteriously deleted
Note that in empwatch "ten days old" is based on the atime (file access time) by default, but recent (last 3 years) versions of Fedora have a tmpwatch script configured to consider all of atime, mtime, or ctime. If you have your filesystem mounted as noatime, or are putting your files into /tmp with some method (like extracting from an archive) which sets old times, that might explain their "early" disappearance.
Feb
25
comment Using SSD as disk cache
See also serverfault.com/questions/239808/ssd-for-swap-on-ubuntu-server/…, which is about swap, but the same caveats apply.
Feb
25
comment Official online RPM package browser / search for CentOS
You may also be interested in EPEL fedoraproject.org/wiki/EPEL
Feb
25
comment Official online RPM package browser / search for CentOS
It's not a web interface, but you can search packages and get metadata information with yum search and yum info.
Feb
24
comment Passing variables problem - Bash
I just tested this in half a dozen versions of bash, and it acts the way Iain and I expect. Something doesn't add up here.
Feb
24
comment Passing variables problem - Bash
Yeah, that's really weird. Bash doesn't normally work like that — brace expansion happens before $ expansion, so normally you'd get what Iain says in the comment above.
Feb
18
comment Central authentication and /home storage with caching
I'd really caution anyone against any serious new deployment of AFS. And I can't imagine someone wanting to inflict administration of it on themselves for a home network. As a specific point, while it supports client caching, disconnected operation is a different story. There's some unfinished experimental code in the development tree if you really want to be on the bleeding edge of deep left field.
Feb
17
comment What is cloud computing?
See also: serverfault.com/questions/206703
Feb
8
comment Should I use GlusterFS as storage pool for KVM/Xen virtual machines?
What's the question here exactly?
Feb
8
comment I have a perl script that is supposed to run indefinitely. It's being killed… how do I determine who or what kills it?
Running out of memory? Check the logs for oom killer messages.
Feb
8
comment Is there a diff/merge utility to compare binary files and synchronize data bit-by-bit in either direction based on differences in binary data?
If the data is valuable enough to go to all that trouble, why not use ddrescue as intended? (And, in 20/20 hindsight, why isn't it backed up elsewhere?) ddrescue does what you want not by treating zeros as magical but by deciding to overwrite based on whether it got errors. (It'll never write out new bad-read zero blocks.)
Feb
8
comment Is there a diff/merge utility to compare binary files and synchronize data bit-by-bit in either direction based on differences in binary data?
I think you should change the subject of your question to reflect that you're not looking for a general-purpose tool to synchronize based on just any differences in binary data.
Feb
8
comment Is there a diff/merge utility to compare binary files and synchronize data bit-by-bit in either direction based on differences in binary data?
Yeah, rsync doesn't care about your special-case.