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 Yearling
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Apr
17
comment Fixing terrible performance when watching/reading video and writing video files to disk
If you have source code access to the downloader, see whether using memory mapped files would help. I'd try: 1. Use the deadline scheduler. 2. Try to bunch up your writes into few large consecutive writes instead of many small writes (IOPS vs Throughput). 3. Tell your downloader to stop abusing the vm cache (posix fadvise). 4. ionice the downloader to a lower priority and the reader process to a higher priority. 5. Have a look at /prov/sys/vm/[dirty-ratio, dirty_bytes]. Playing with this variable will influence your writeback behaviour. linuxinsight.com/proc_sys_vm_dirty_bytes.html
Apr
17
comment Fixing terrible performance when watching/reading video and writing video files to disk
Have you tried looking at the VM subsystem hints? POSIX fadvise that is? You may find that the download process is trashing your VM cache. Download linux-ftools and wrap the download/write to disk script with fadvise dontneed and see what happens. code.google.com/p/linux-ftools
Apr
17
comment How to create a fake inotify event on debian?
Can you touch a zero sized hidden file? Say your media files are in /var/blah/media/pictures. Just touch a .touchme and that should generate the correct inotify event. Would this work?
Apr
17
comment What is the IPsec bottleneck in Linux?
Hmm, that is interesting. I'd suspect that something in the kernel is slowing things up. Would you mind sharing your ipsec configuration? I'd like to instrument a VM and see what results I'll get with different settings.
Nov
5
comment Disk is a bottleneck. Background processes make things worse. How to improve responsiveness?
YMMV: We did try to play around with swappiness unsuccessfully. We tried all kind of values, graphed stuff and didn't get anywhere. We eventually ended writing up a daemon that would evict the pages of certain misbehaving programs every few seconds from the page cache.
Nov
5
answered Dovecot/Postfix mail server replies to [SYN] with [RST, ACK] when user attempts to connect (POP3). Likely iptables?
Nov
5
answered First sudo always slow
Nov
5
awarded  Yearling
Nov
5
revised Disk is a bottleneck. Background processes make things worse. How to improve responsiveness?
added 559 characters in body
Nov
5
answered Disk is a bottleneck. Background processes make things worse. How to improve responsiveness?
Aug
20
answered Redirecting loopback traffic through a router
Jun
10
awarded  Populist
Aug
17
awarded  Yearling
Jul
28
awarded  Good Answer
Jun
21
awarded  Yearling
Nov
7
awarded  Nice Answer
May
26
comment Really light weight linux for VM no extensions
You could try instantiate a simple vm with virtio on. Or maybe edit the config for your existing vm and see.
May
23
answered blocking facebook.com outside facebook.com domain
May
23
comment In Debian 6, how to start a daemon as a different user?
I can see in my rc.d that the debian daemon starter can accept users `grep -nire start-stop-daemon /etc/init.d/ /etc/init.d/xpilot-ng-server:35: start-stop-daemon --start --quiet --chuid $USER --background `
May
23
answered Really light weight linux for VM no extensions