Re: softupdates recommendation

[Marco Peereboom <marco@peereboom.us>]

I use softupdates just about everywhere. Sure there are corner cases where one 
can loose some data however I (usually) prefer the performace boost over the 
potential to loose data. Keywords here are UPS, stability and easily 
recreated/restored data.

IDE stinks it can have one whole pending IO (the new ones can have 2!! woohoo 
one read and one write). SCSI on the other hand can have many pending IO's 
depending on your disk it is usually between 16 (old!) and 128(new!) pending 
IO's. This is the same idea as running a single or multi threaded 
application.

IDE is CPU intensive, unlike SCSI which does pretty much everything on it's 
own and just lets the OS know when it is done.

Add all this up and you'll notice that SCSI is an order of magnitude faster 
than IDE. Even though the lines are blurring with newer technology IDE and 
SCSI are both here to stay. IDE is good enough for PC's and SCSI is moving up 
the chain to challenge FC when SAS launches.

IDE yuck! SCSI good :-)

On Wednesday 02 July 2003 12:06 am, Sancho2k.net Lists wrote:
> I was hoping to get a group concensus on the use of softupdates.
>
> The FAQ says that "Soft Updates are still in development as a whole" but
>   they do sound mighty appealing.
>
> Are softupdates used my many without a great danger relating to the
> problems discussed?  Can I consider it safe to implement them on
> filesystems used heavily with a lot of disk activity to generally speed
> the system up?
>
> One area that I wanted to try to improve (without forking out $$$ for
> scsi host adaptor and disks) was the performance of the system during
> anoncvs updates. My vmstat output looks like this during it:
>
> procs   memory        page                    disks     faults     cpu
>   r b w    avm    fre   flt  re  pi  po  fr  sr wd0 cd0   in    sy   cs
> us sy id
>   1 7 0 111908 484404   215   0   0   0   0   0   8   0  243   522   25
>   2  1 98
>   0 7 0 111912 484400   279   0   0   0   0   0  59   0  296   569   84
>   1  1 98
>   0 7 0 111912 484400   709   0   0   0   0   0  27   0  261   821   53
>   2  2 96
>
> I understand that the 7 in the second column indicates that my disk is
> blocking and is the bottleneck. Will softupdates drastically improve
> this? (ATA 66 7200 IDE disk.)
>
> TIA for the responses,
>
> DS