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Date:      Mon, 17 Nov 2008 17:18:33 +0100
From:      Sossi Andrej <asossi@dotcom.ts.it>
To:        freebsd-stable@freebsd.org
Subject:   swap_pager: indefinite wait
Message-ID:  <49219959.8040209@dotcom.ts.it>

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Hello,
I manage a www (apache), database (postgresql) and e-mail (qmail) with
about 100 Internet domains.
We recently purchased  a DELL MD3000i server with data access through
ISCSI protocol.
I installed  a new server with FreeBSD 7.0 compiled kernel with ISCSI
(v. 2.1) and SCHED_ULE scheduler.
The server's local disk configuration is:
512 MB /
1024 MB SWAP
254 MB / var
2048MB / var/ qmail
512 MB /tmp
~ 70 GB /usr

The apache data (/usr/local/www), postgre (/usr/local/pgsql) and qmail
(/usr/local/vpopmail) are instead on the partition on ISCSI. After
installing all the necessary softwares I tested the machine as mail
server for a one domain and everything worked fine for 2-3 days.
I wanted to test the correct functioning of qmail and of the
reading/writing on ISCSI. On the end of testing I  decided to transfer
all of data (www, DB and e-mail) on the FreeBSD 7.0. I compressed all
the data on the original server (on tar.gz format). I transferred them
on the new server and started to decompress the files. Www data have
been decompressed correctly on the ISCSI disk. But while the messages
were being decompressed (~80GB of tar.gz) and all the DB were being
restored, the server crashed.
The error shown was:

swap_pager: indefinite wait buffer: bufobj: 0, blkno: 31, size: 4096

This message repeated every 30 seconds.
While restarting with the single user mode I checked there wasn't any
message after the crash in /var/log/messages.

I think 1GB of swap should be enough, since with this configuration on
FreeBSD 5.5 everything worked for over 270 days without reboot.
The local disks are 2 of ~80GB in RAID 1 (mirror) with Gmirror
before installing FreeBSD I tested the 2 disks with the badblocks
software on Slackware which didn't find any r/w error.

Can somebody help me understand why the system crashed this way or how
to avoid future crash?
It's a production server and I can't afford an out-of-service or data loss.

Thank you very much and kind regards.

-- 
Sossi Andrej
-------------------------
DotCom Information technology

Via Biancospino, 9
34151 - Opicina (TS)
Italy

tel: +39 040 2158191
fax: +39 040 0641954
E-mail: asossi@dotcom.ts.it
----------------------------

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