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LWN.net Weekly Edition for May 16, 2013
A look at the PyPy 2.0 release
PostgreSQL 9.3 beta: Federated databases and more
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(Nearly) full tickless operation in 3.10
Fedora's purpose is according to http://fedoraproject.org to "showcase the latest in free and open source software", which doesn't sound much like "run a very busy server".
I would have guessed they would be running Debian Stable or some Ubuntu LTS release, so what's the reasoning behind running Fedora?
Posted Jul 23, 2009 9:19 UTC (Thu) by sasha (subscriber, #16070)
Posted Jul 23, 2009 11:45 UTC (Thu) by epa (subscriber, #39769)
That means that upgrading the machines should not be a 'long process' as they report; it is essential to have an automated way to push out the latest distribution and to be able to swap out machines for spares. Otherwise, yes, you are making a rod for your own back.
Posted Jul 23, 2009 11:56 UTC (Thu) by Thue (subscriber, #14277)
Posted Jul 23, 2009 13:06 UTC (Thu) by regala (subscriber, #15745)
my experience showed me that 2 years of development in FOSS can bring you more than expected changes of config formats, db on-disk formats...
it is a matter of choice, but 1 year is not that short in FOSS community.
Posted Jul 23, 2009 14:51 UTC (Thu) by epa (subscriber, #39769)
If you can't do this, and you have particular machines which have to stay up, and odd bits of configuration meaning you cannot install a new box fully automatically, then Fedora is probably not a suitable choice. (Myself I package almost everything as RPMs, and keep locally modified /etc files in version control, so installing a new server from scratch is not too painful. I would automate it even further if I had more than one box to worry about.)
Posted Jul 26, 2009 20:59 UTC (Sun) by jlokier (guest, #52227)
Which creates a dilemma, if you need a newer OS for some service but don't want to break the other services by doing the upgrade.
VMs help a lot with this, but they take a lot of resources and can't always be used.
Posted Aug 1, 2009 10:12 UTC (Sat) by Lennie (subscriber, #49641)
Posted Aug 1, 2009 14:16 UTC (Sat) by jlokier (guest, #52227)
There is that slight problem that you don't have different kernels under Linux-VServer, so older distros which break with later kernels won't work. The kernel's system call interface is backward compatible, but many other things which "system-level" utilities depend on are not, and those are needed to boot an old distro without spending lots of time tweaking it.
So, not so good for booting old distros, but fine for running applications on those distros provided they don't depend on a booted environment. E.g. it's great for running old versions of GCC.
What KVM is great for is taking an old, working machine (say using a Linux 2.4 kernel or earlier, or Windows of course) and migrating it into KVM on a new machine with almost no work at all.
So: KVM for old Linux images and other OSes where you need a fully booted environment; Linux-VServer or LXC for almost current images, or running applications on old images which don't need a booted environment.
Posted Aug 1, 2009 18:47 UTC (Sat) by Lennie (subscriber, #49641)
Actually, most VServers don't need much boot and/or system-level stuff.
You could say it runs only starts/runs those scripts which usually get run at init level 2 or 3.
VServers don't handle anything them selfs, like mounting /tmp or setting up networking. The /dev directory is mostly empty only null and zero and stuff like are needed.
Yes, going from physical to vserver might be more work (stripping out stuff you don't need). I've never seen any problems with kernel-dependencies.
Posted Aug 2, 2009 5:29 UTC (Sun) by jlokier (guest, #52227)
It's also fine if you already have your apps set up to use it, naturally.
When it's less inviting is when the problem is to keep some old app working that's currently on a real machine running some old distro. KVM is quite good at making that work with minimal effort.
I put mail serving (anything other than a simple configuration) in the latter category, because these days a mail server is a fairly complex affair and will run alongside a couple of spam filtering daemons and virus filtering daemon and some delivery program or other, maybe also user's procmails and perhaps involving the IMAP service too, and undoubtedly depends on a few non-obvious files in /etc as well as the obvious ones. That's the sort of thing I mean by "if I don't have time to touch this now, I can't afford to be updating the OS on this server to a newer version". Repeated prior experience tells me such things break on OS upgrades and can take a long time to get working again with the same behaviour as before.
Posted Jul 23, 2009 12:11 UTC (Thu) by Velmont (guest, #46433)
Posted Jul 23, 2009 14:49 UTC (Thu) by xoddam (subscriber, #2322)
Not that you can't run Fedora 9 on a new kernel, but that would not seem to be a compelling reason for the choice of distribution.
Posted Jul 24, 2009 7:29 UTC (Fri) by nix (subscriber, #2304)
Upgrade conservatism is definitely called for here.
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