XO-1.5 slow disk writes

Martin Langhoff martin.langhoff at gmail.com
Wed Nov 18 05:14:47 EST 2009

On Tue, Nov 17, 2009 at 7:03 PM, Benjamin M. Schwartz
<bmschwar at fas.harvard.edu> wrote:
> Of course, getting sync to be very fast would also be nice.

There was some discussion a while ago in lkml about a "more eager to
blush buffers" async mode. Basically, if the system is reasonably idle
and there are buffered writes, write them out without waiting the
usual 5s.

It makes sync virtually instant unless the system is loaded, at the
expense of a bit more fragmentation (not an issue on flash, except
that it may incur on a few more erasecycles).

It even got a moniker, and I think I saw it an implementation either
on ext3 or vfat. It was mainly thought as a good mount option for
removable drives -- reducing the impact of users removing the USB disk
if they see no blinking lights.

And damn I can't remember the name or anything googlable about it.

 martin.langhoff at gmail.com
 martin at laptop.org -- School Server Architect
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