Large Ramdisk creation causes crashes

[Andy Green]

Brandon Ooi wrote:

Hi Brandon -

> Sorry that wasn't an exact transcript. I was actually doing...
> 
> perl -e 'print 1 x 600000000' > /mnt/r0/file0
> 
> which fills the drive and then stops. This seems to work as long as the
> total number of 1's I write to ram is less than 40% of total memory I
> have (regardless of how large the ramdisks are or how many I create).

Again in this particular example you create a file 120% of the ramdisk,
but as you say you fill it with smaller amounts I guess that is not it.

> I have created 10MB and 100MB ramdisks which seem to work fine. Writing
> and rewriting work as expected (and fast!). It's only when I create more
> and larger drives do I encounter problems.

Hm well then I would wonder what is crashing... it can be when memory is
allocated to the ramdrive because pages are in use, or it can be to do
with the filesystem.

dd if=/dev/urandom of=/dev/ram0 bs=1024 count=450000

should allocate 450MB of storage to the 512MB max ramdrive device
without requiring or using a filesystem.  If that crashes then it seems
it is a kernel problem with ramdrives and Bugzilla beckons.

If it does not crash, it can be a problem with ext2.... format the thing
vfat and try your original tests again.

-Andy
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