OS Defrag?

My 220GB DB resides mostly on one RAID 5 logical drive. This drive reports
fragmentation. Will I see any potential improvements in disk access if I
choose to defrag? Due to text columns and fairly large/wide rows,
performance is rock bottom. As a for instance, I have a 2.2GB file and
shrinking 1MB ran overnight without completing.Yes, it can help. see
http://www.microsoft.com/technet/abouttn/subscriptions/flash/tips/tips_083104.mspx
for more details.
Why are you trying to shrink your data files btw?
--
Paul Randal
Dev Lead, Microsoft SQL Server Storage Engine
This posting is provided "AS IS" with no warranties, and confers no rights.
"Jeffrey K. Ericson" <JeffreyKEricson@.discussions.microsoft.com> wrote in
message news:90631664-5FA2-4EC2-93FC-CBA5F47ADD8E@.microsoft.com...
> My 220GB DB resides mostly on one RAID 5 logical drive. This drive
> reports
> fragmentation. Will I see any potential improvements in disk access if I
> choose to defrag? Due to text columns and fairly large/wide rows,
> performance is rock bottom. As a for instance, I have a 2.2GB file and
> shrinking 1MB ran overnight without completing.|||The original problem was the disk performance, specifically disk reads, was
slow enough to make the system unusable. I since discoved that the purging
of some historical tables had a dramatic effect on what objects where in
cache which virtually eliminated the disk reads. The 220GB database was in 4
files on one logical drive(80GB, 40GB, 40GB, 40GB). I had created an
additional file on the same logical drive before creating files on other
logical drives in hopes of spreading out this and other DBs across 3 logical
drives each on their own channel. For the smaller database, this worked out
OK. For the 220GB DB, there are several GB free in each file. Neither DBCC
shrinkfile(emptyfile) or truncate_only finish and eventually deadlock. For
the smaller DB, I wrote a loop that shrunk the files a few MB at a time. I'm
trying to close the large files so no more data gets written to them. At 80
and 40GB, the files are too large to manage given my current level of
performance.
"Paul S Randal [MS]" wrote:
> Yes, it can help. see
> http://www.microsoft.com/technet/abouttn/subscriptions/flash/tips/tips_083104.mspx
> for more details.
> Why are you trying to shrink your data files btw?
> --
> Paul Randal
> Dev Lead, Microsoft SQL Server Storage Engine
> This posting is provided "AS IS" with no warranties, and confers no rights.
> "Jeffrey K. Ericson" <JeffreyKEricson@.discussions.microsoft.com> wrote in
> message news:90631664-5FA2-4EC2-93FC-CBA5F47ADD8E@.microsoft.com...
> > My 220GB DB resides mostly on one RAID 5 logical drive. This drive
> > reports
> > fragmentation. Will I see any potential improvements in disk access if I
> > choose to defrag? Due to text columns and fairly large/wide rows,
> > performance is rock bottom. As a for instance, I have a 2.2GB file and
> > shrinking 1MB ran overnight without completing.
>
>