Show stopper for large disks with 5.4-RELEASE

Pierre DAVID Pierre.David at crc.u-strasbg.fr
Wed Jun 8 12:31:40 GMT 2005


Hi,

we are setting up a mail server for ~50 000 users, with around 1.8TB
on a DAS storage (HP MSA 500).

We were planning to use FreeBSD (5.4-RELEASE), as with all other
servers in our machine room.

However, we are encountering a show stopper: after an unclean
shutdown, the snapshot that fsck creates is taking too much time
(more than 20 minutes). During the most part of this time, all I/O
are frozen on this large disk, so the server cannot serve our
clients. Our SLA constraints do not allow us to have these recovery
times.

The options used to create the file system were standard sysinstall
options. During normal operations, performances are very good.

Our tests showed that Linux doesn't present the same problem. With
ReiserFS, the reboot after crash takes only 20 seconds to read the
journal and recover the file system.

Is the snapshot time for large volumes a known problem? We don't
see such a long time with smaller file systems.

Do you have a clue to help us use FreeBSD and not switch on Linux
for this service?


Philippe Pegon & Pierre David


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