Differences
This shows you the differences between two versions of the page.
internet:self-hosting [2011/12/25 21:31] cyril [Flash cache] |
internet:self-hosting [2013/09/19 16:40] |
||
---|---|---|---|
Line 1: | Line 1: | ||
- | ====== Website Self Hosting ====== | ||
- | |||
- | ===== IP ===== | ||
- | |||
- | Dynamic DNS service if you don't have a static IP. | ||
- | |||
- | ===== Hardware ===== | ||
- | |||
- | Any old machine, or even better an old laptop (less power, less noise, less room). | ||
- | |||
- | ==== Flash cache ==== | ||
- | === Introduction === | ||
- | Solutions for hybriding flash drives and hard drives have been experimented to save power on laptops, but it is quite complex in the general case and there is no final-user implementation yet, and the gains are limited on an everyday use machine. However it is a lot more efficient and simple on a server, as there are a lot less interactions with users and the panel of activities is largely reduced. Hence you only have to put on flash disk a few directories and files that the system regularly write to (the cache in RAM is enough for reading), and the disk can remain spun down for hours or days if you don't start unusual applications. | ||
- | |||
- | You need an USB stick or SD Card of at least 2GB (4GB is advised), and an init script to mount and fetch during early boot process, and unmount and flush during late shutdown process. For instance I wrote this one for Gentoo: [[init_fcache|/ | ||
- | |||
- | As an example, my server (a Core2 Duo laptop) consumes 12-13W (saved 1W stopping the hard drive), makes no noise at all (no fan, no hard drive), and the hard drive remains stopped for several days, as long as I don't do something unusual (I can even log in with ssh, with export display, as root, use firefox, without waking up the drive). | ||
- | |||
- | === What to cache === | ||
- | |||
- | The main directories you need to take care of are: | ||
- | * ''/ | ||
- | * ''/ | ||
- | * ''/ | ||
- | |||
- | If you cannot cache your whole home folder, you can cache a few files that are updated too often by putting them in a '' | ||
- | * '' | ||
- | * '' | ||
- | * '' | ||
- | * '' | ||
- | * for GDM: set '' | ||
- | * for SSHD: set '' | ||
- | * for SU: set '' | ||
- | |||
- | ''/ | ||
- | * ''/ | ||
- | |||
- | === Configure smartd === | ||
- | |||
- | If you run '' | ||
- | <code diff> | ||
- | -DEVICESCAN | ||
- | +# | ||
- | +/dev/sda -d ata -n standby | ||
- | </ | ||
- | |||
- | === Finding the guilty files === | ||
- | |||
- | You can use a script similar to this one to monitor what files are being used and add them to the cache (you can then grep " | ||
- | <code sh> | ||
- | #!/bin/sh | ||
- | |||
- | rm -f / | ||
- | dmesg -c | ||
- | #sudo sysctl vm.block_dump=1 | ||
- | echo 1 > / | ||
- | watch --interval=5 'dmesg -c | grep sda >> / | ||
- | echo 0 > / | ||
- | </ | ||
- | You can also use '' | ||
- | |||
- | === Configure the drive to go to standby === | ||
- | |||
- | Configure hdparm to put the drive to standby after some time of inactivity. For instance to test with 10 minutes: | ||
- | < | ||
- | hdparm -S 120 /dev/sda | ||
- | </ | ||
- | |||
- | And for final configuration copy ''/ | ||
- | |||
- | === Optional extra configuration === | ||
- | |||
- | You can try to tune how syslog will write to the disk to save the flash life, in ''/ | ||
- | < | ||
- | options { | ||
- | mark_freq(0); | ||
- | flush_lines(20); | ||
- | flush_timeout(60000); | ||
- | }; | ||
- | </ | ||
- | |||
- | === Read cache === | ||
- | |||
- | You can try to prefetch in the Linux RAM read cache all the programs and files you often read, with a script that executes programs and grep inside files. | ||
- | |||
- | You can also have a look at '' | ||
- | |||
- | === RAM write cache === | ||
- | |||
- | You could also try to use the '' | ||