SSD and Disk Cache

[berentzp]

Hi

I am now running my computer with an SSD as system disk (Corsair Performance Series P128).

SSDs are not recommended for intensive disk writing and in particular OS memory swapping is discouraged.

Is it safe for the SSD to be used for Photo Mechanic disk cache, or should I be using one of my old hard drives?

I am running PM v. 4.6.2.1 on Win7 Pro, 4GB RAM.
AMD Phenom II X4 965.

Thanks
Peder

[Kirk Baker]

Peder,

I am now running my computer with an SSD as system disk (Corsair Performance Series P128).

SSDs are not recommended for intensive disk writing and in particular OS memory swapping is discouraged.

Is it safe for the SSD to be used for Photo Mechanic disk cache, or should I be using one of my old hard drives?

Photo Mechanic's caching system does write a lot of files to its cache when browsing photos.  But once it generates a thumbnail, it is only written once, and read many times.  It isn't like virtual memory where a particular sector of the disk is rewritten many thousands of times.

We can't be held responsible for any drive failures if you use Photo Mechanic on your system.

How many write cycles can a sector handle before it fails?
If your system only has the internal SSD and you use too much memory and virtual memory would kick in, does the system just run out of memory or does it just do VM paging anyway?

-Kirk

[Hayo Baan]

As a general rule I would not put any cache data on an SSD. This would include PM's cache, even though as this is more of a write once, read many times type of thing as Kirk suggested.

Cheers,
    Hayo

[berentzp]

Peder,

I am now running my computer with an SSD as system disk (Corsair Performance Series P128).

SSDs are not recommended for intensive disk writing and in particular OS memory swapping is discouraged.

Is it safe for the SSD to be used for Photo Mechanic disk cache, or should I be using one of my old hard drives?

Photo Mechanic's caching system does write a lot of files to its cache when browsing photos.  But once it generates a thumbnail, it is only written once, and read many times.  It isn't like virtual memory where a particular sector of the disk is rewritten many thousands of times.

We can't be held responsible for any drive failures if you use Photo Mechanic on your system.

How many write cycles can a sector handle before it fails?
If your system only has the internal SSD and you use too much memory and virtual memory would kick in, does the system just run out of memory or does it just do VM paging anyway?

-Kirk

Kirk,

Thanks for your reply.

I don't know how many times an SSD can be written to before it becomes unreliable. I believe that the number is increasing with every new generation and that by now it is in the millions. Don't quote me on that number though.

Does PM write the thumbnails once per session, or once ever?
Especially in case of the latter I would think it to be safe to cache to the SSD.

I believe Win7 defaults to caching to the SSD system disk. However it has detected that it is and SSD and disbled defrag for that disk only.

- Peder

[Kirk Baker]

Peder,

I am now running my computer with an SSD as system disk (Corsair Performance Series P128).

SSDs are not recommended for intensive disk writing and in particular OS memory swapping is discouraged.

Is it safe for the SSD to be used for Photo Mechanic disk cache, or should I be using one of my old hard drives?

Photo Mechanic's caching system does write a lot of files to its cache when browsing photos.  But once it generates a thumbnail, it is only written once, and read many times.  It isn't like virtual memory where a particular sector of the disk is rewritten many thousands of times.

We can't be held responsible for any drive failures if you use Photo Mechanic on your system.

How many write cycles can a sector handle before it fails?
If your system only has the internal SSD and you use too much memory and virtual memory would kick in, does the system just run out of memory or does it just do VM paging anyway?

I don't know how many times an SSD can be written to before it becomes unreliable. I believe that the number is increasing with every new generation and that by now it is in the millions. Don't quote me on that number though.

Does PM write the thumbnails once per session, or once ever?
Especially in case of the latter I would think it to be safe to cache to the SSD.

It depends on your Photo Mechanic Disk Cache settings and your usage patterns.  The simplest answer is that it is quite possible for a cached image to be created, deleted and created again, many times over.  For instance if you have the Disk Cache set to empty on quit then each time you quit PM the Disk Cache is deleted and when you start up again, images will get cached again.

-Kirk

[berentzp]

Kirk,

I will untick "Empty cache on exit" and "Remove cached files that are older than _X_ days old". (Or set the latter to a high value - I shall see how quickly I fill up my cache area.)

From what you are saying and with my relatively low volume of usage I feel that it is safe enough to cache to SSD with these settings.

I know that you can not guarantee against implications and that I will do it on my own risk. The improvement in performance though should be worth it.

It would be nice if you can post more on this topic as you get more experience with it.

Thanks for your advice!
- Peder