Subject RE: [ib-support] IB Newbie: multi file databases and shadowing
Author Leyne, Sean

With respect to multi-file databases:

This issue will soon be less important, for users of the Firebird
engine, as we are working on an engine update which will allow for a
single database file to grow to terabytes in size (instead of the
current 2gb limit for *nix and 4Gb for NT).

It will still be necessary to use multi-database when the database grows
larger than the logical drive it is stored on. This is also becoming
less of an issues as advances in disk drive sizes and as RAID
controllers become standard equipment for servers.

I can't speak to any performance issues for multi-file databases, I've
never used them.

With respect to shadowing:

In theory, using shadows results in a 100% slowdown in disk write I/O
operations. This, however, is really dependent on the database's Forced
Write setting (although why someone would enable shadowing but turn off
Forced Writes, is beyond my understanding) and the server hardware/disk

Bottom line is "your mileage will vary" depending on whether you have: a
dumb disk controller, a cached disk controller with 64Mb, a drive with
no cache, a drive with 2Mb cache, IDE, SCSI, FibreChannel, RAID 1,


-----Original Message-----
From: Lutz Kutscher [mailto:LKutscher@...]
Sent: Friday, February 23, 2001 3:29 AM
To: Interbase Support Newsgroup
Subject: [ib-support] IB Newbie: multi file databases and

Hi y'all,

I've been watching this newsgroup for a few days now, and I hope, it is
right one for my questions.

1) multi file databases
I've read a lot about the advantages of a multi file database on IB /
Are there any disadvantages / drawbacks für spanning a database to
Especially considering access-times for tables?

2) shadowing
I'm sure, shadowing can't be done without some loss in performance.
Is there any way to determine, how big that performance loss will be?

BTW. I don't need direct answers, if you just point me to some document,
where I can find out more about those topics, I'll be happy.