7.2 dies in zfs

[Ollivier Robert]

According to Stefan Esser:
>If your i386 based system has much RAM (2GB or more), than you
>should definitely increase KVA_PAGES. Not doing so will lead to
>panics, not in spite of but exactly because of the large RAM.

I have uppped KVA_PAGES of course but this is reducing the amount of memory available to processes.  If you define KVA_PAGES to 2GB for example, every process will be able to use only the remaining 2 GB for their own memory so there is a trade off there.

>I have been using ZFS on i386 since it became available, first for
>testing and soon as only file-system (with UFS boot, initially, now
>switching over to gptzfsboot). Systems range from Pentium-3 to
>AMD64x2 and I see no problems even under significant load.

I've found that load is not a factor (if one defines load as many concurrent processes).  The machine is mostly idle and I've seen panics coming from a "cvs update" or a "svn up".  There are I/O intensive but not that much whereas the same machine can survive a buildworld just fine.

The machine I have is a dual Xeon @2.8 GHz with 4 GB of RAM and 200 GB of disk.

/boot/loader.conf
-----
#-- limits
kern.maxdsiz="1024M"
kern.maxssiz="256M"
kern.dfldsiz="1024M"
kern.dflssiz="128M"

#-- vm tuning
vm.kmem_size="1024M"
vm.kmem_size_max="1224M"
vfs.zfs.arc_max="128M"
vfs.zfs.prefetch_disable=1
-----

options         KVA_PAGES=384           # 1.5GB of KVA

-- 
Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto at keltia.freenix.fr
In memoriam to Ondine : http://ondine.keltia.net/