Re: Dom0 starvs DomU

[tg%gmplib.org@localhost (Torbjörn Granlund)]

Manuel Bouyer <bouyer%antioche.eu.org@localhost> writes:

  did you try disabling '-o log' ?
  WAPBL will do lots of disk cache flushes, which can hurt ...

I have installed NetBSD as a Dom0 many, many times.  I've done it on all
sorts of hardware and using many versions of NetBSD and Xen.  Usually I
recall to put ",log" in fstab, but not always.

Please understand that I have yet to hit a (NetBSD release x Xen release
x configuration) where compiling in Dom0 does not make DomU disk
operations outragously slow.

The underlying disk speed does not seem to be a factor.  (I used to have
spinning rust, now most systems run top-of-the-line SSDs.)

Instead of asking me to try more configurations, please consider trying
to reproduce this.

I needed to solve this, and it does not seem a NetBSD fix is to be
expected any time soon.  Therefore, as an intermediate solution I have
moved many of our test systems to GNU/Linux/Xen.  I'd love to move them
back.

But I need the starvation issue fixed for my usage.

I also need installation on modern PCs to work reliably.  Now, most
systems stop because they cannot find the root file system of the
install media (tested: USB stick or USB CD unit).  (I have worked around
this by removing disks to temporary systems which can boot NetBSD
install media.  This is not very practical...)

I also need reboot to work reliably.  Now, a NetBSD "reboot" too often
hangs after having synched disks.  Not cool for co-located systems
without PDU.

-- 
Torbjörn
Please encrypt, key id 0xC8601622