LR to PS & back consumes home drive space; stop it

Question

I notice when I do a lot of back & forth LR4 - PSCS6, my start up drive is getting overly used for something to the point of choke.
I dont want this.  I have directed all activities to external scratch drives, but something is chewing up my space in this case, to the tune of about 6-9 GB.
Well, that's all the space left on my SSD, and I dont want to buy more ssd's cuz of this; my ssd works great until this happens.
Anyone?
Thanks
steve z
mac osx.7.4
16GB ram,
2.236 GHz quad core intel xeon

Answer 1

I am not sure what you mean by "my start up drive is getting overly used".
Do you mean that your drive gets more and more full, or do you mean that your drive is very busy, i.e. doing lots of read-and-write cycles?
If the former is true, see Jeff Schewe's comment.
If the latter is true, you might have too much going on one-and-the same drive. You say "I have directed all activities to external scratch drives." But where is the Lr catalog? Lr constantly writes to and reads from the catalog. When you work in the Develop Module with each new step the whole data set is reloaded. Then there is activity for the Lr cache.
It therefore helps to divide the Lr tasks to different drives.
This is what I wrote in an earlier post:
In my experience sharing the workload between several drives will give a significant performance boost.
Naturally, faster hard drives (10K conventional or SSD) will speed up performance in any configuration. But as long as prices for 400 - 500 GB SSDs are relatively high and their life expectancy is somewhat iffy, it might be worthwhile considering the concept of sharing the work between several drives.
Here's my system: I have 3 internal hard drives (7200 RPM, 500 GB each), named C, D, E.
On C there is the OS and Lr.
D is dedicated only for paging file (I'm on Windows), Lr cache, Photoshop scratch disk.
E contains the Lr catalog.
Images are on external hard drives.
This setup avoids read- / write competition between OS paging file, Lr cache, Lr catalog, and image files and provides good performance in Lr.
In my opinion, the slow performance of Lr that some people complain about, might be due to
a) cache too small (I have set mine at 75 GB, Adobe recommends 25 GB, but the Lr default is 1 GB);
b) read-/write competition due to the fact that images, catalog, and Lr cache are on one hard drive. Keep in mind that Lr constantly reads from and writes to the catalog. If the images, the Lr cache and OS (with paging file) and Lr itself are all on one drive, the read-/ write cycles for this drive pile up and slow Lr down.
Certainly, a SSD has much faster read- / write times, so it will alleviate the problem of read- / write competition. But as long as they are expensive and have - maybe(?) - short life times, it might be worthwhile to install at least 2 - but better 3 - conventional hard drives and so that the workload can be shared between them.
See also her what Adobe says about improving performance of Lr: http://helpx.adobe.com/lightroom/kb/optimize-performance-lightroom.html#main_Render_1_1_pr eviews_intentionally