Re: diff between raw device and ufs in solaris

rvag wrote:
>
> I just got in a client site to replace a dba for a short period
> of time(2-3 months), I find the datafiles are in ufs filesystem
> instead of raw devices
> OS Solaris 2.6
> Oracle 8.0.5
> How much of a performance gain would I get by moving all the
> datafiles to a raw devices, assuming the db operations here
> quite a I/O intensive, the client cannot afford a big downtime,
> not really quite easy to justify to the client to buy more
> hardware due to some internal situations
> Is it worth the trouble?
> Will a datafile created under ufs would work as expected if
> transferred to a raw device directly?
>
> Your suggestion and comments would be greatly appreciated.
>
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Check the other posts .. although I've never really understood the supposed 'complexities' of raw devices - I've always found them easy enough to setup/admin etc...

One quick fix would be to turn on the 'forcedirectio' option on the file systems (in vfstab). This bypasses the unix file buffers and thus gets you some of the way toward raw performance.

One area to look at is the amount of sorts to disk - if there is a lot, make sure you have many (as opposed to one) datafiles for the TEMP tablespace - since inode locking in ufs can cause nasties.

HTH

-- 
===========================================
Connor McDonald
http://www.oracledba.co.uk

We are born naked, wet and hungry...then things get worse