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Bug#862013: also it can be too big

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On systems with large amounts of RAM allocating 10% for /run is also 
undesirable.  My latest server has 48G of RAM (not really big by server 
standards) and I don't want a runaway process writing to /run to consume 4.8G 
of RAM before it is stopped.

/dev has no size specified in /usr/share/initramfs-tools/init so it gets half 
of RAM as the default tmpfs size.  It's not that uncommon for a script to 
write to a file under /dev thinking it's writing to a device (a typo in /dev/
null when running as root is a common example).  I would prefer to mitigate 
the damage that such accidents can cause by reducing the size of /dev.  I 
can't imagine anyone needing more than a few dozen megs for /dev anyway.

Also the number of inodes is set to half the number of pages.  On a system 
with 48G of RAM that means 6182147, which is well in excess of anything you 
need in /dev or /run.  Presumably some kernel memory is taken for the inodes 
or something, otherwise it would default to 2^32 or something.  So reducing 
the number to something reasonable seems sensible.

I've experimented with setting both /dev and /run to 200M and 4096 inodes and 
it seems fine.

But ideally it would be best to allow the sysadmin to easily tune these things 
without editing /usr/share/initramfs-tools/init.  Maybe make /usr/share/
initramfs-tools/init a template that is run through sed to generate the actual 
paramaters used when booting from a config file under /etc/initramfs-tools.

-- 
My Main Blog         http://etbe.coker.com.au/
My Documents Blog    http://doc.coker.com.au/

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Bug#862013: also it can be too big Russell Coker <russell@coker.com.au> - 2017-06-17 16:50 +0200

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