Virtual Disks & Sybase

[Eric Bergan]

In article <2919 at esquire.dpw.com> sullivan at DPW.COM (David J. Sullivan) writes:
>
>I've been using Pyramid ``simple'' virtual disks to break up a large
>partition into small chunks for use by my Sybase dataserver.  I do
>this to provide for a small partition that I can mirror, using Sybase
>mirroring, for the master database alone, and well as other partitions
>that I can mirror if needed.
>
...
>The Sybase server uses asynch I/O (AIO).  We've never had a problem.
>
>The latest Sybase release, however, explicitly says not to use the
>Pyramid virtual disk facility.   Bummer.  That means I've either got
>to mirror a very large chunk of disk, and if I want to isolate the
>master database to a single partition, waste a lot of disk space, or go
>into the kernel and hardwire in smaller partitions.
>
...
>Can anyone shed any light as to whether or not their exclusion is
>reasonable?  I can certainly understand them being concerned about
>virtual disks spread across different disks types, but my set up seems
>to be fairly benign.

	aio will work with simple, interleave, and mirror virtual disks.
It will work with concat and stripe if the IO does not cross disk boundaries,
and if ordered writes are not required. (Sybase does not currently use the
ordered write facility of aio.)

	I don't think you will have a problem.

-- 

					eric
					...!pyramid!eric