Romex Software Forum

I've just installed the 0.9.1 beta on a Win 7 Pro machine with 16GB RAM and a Samsung 840 Pro series SSD 128GB.

I'm caching 2 1TB Western Digital SATA drives and have allocated 2048MB to the cache and 121500MB to the L2 cache. (basically the entire SSD)

4KB block size, algorithm LFU-R, strategy is Read/Write, Defer-Write disabled.

Seems to be working great so far but I need to run for several days to make a final determination.

Questions I have so far:

• Does this seem like a reasonable starting point for L1/L2cache sizes?
• Under what circumstances does L1 contents get written to L2? on shutdown? when it expires?
• Other than copying files how can I pre-populate L2 cache with files? (large game maps etc)
• Is there a way to list what files or parts of files are in the cache?
• Is there a way to tweak settings without destroying my L2 cache?
• I have plenty of RAM. Should I even bother with invisible memory on a 64-bit OS?
• Does the cache hit rate include L1 and L2 or just L1?

Thanks in advance for your time.

Rob.

RobF wrote:Does this seem like a reasonable starting point for L1/L2cache sizes?

Depends on your data usage. Keep an eye on the performance monitor over a few days to get a better idea of how much data you read/write. I'd suggest, with a 64-bit OS, that you may be able to lower L1 usage with little measurable effect (since Windows has its own file cache doing a similar thing) but if you have memory going spare, you may as well allocate it.

RobF wrote:Under what circumstances does L1 contents get written to L2? on shutdown? when it expires?

Have to wait for Romex to comment on that.

RobF wrote:Other than copying files how can I pre-populate L2 cache with files? (large game maps etc)

Just reading (rather than copying) a file should work, but finding a utility that would read an arbitrarily formatted file would be tricky - a hex editor might be the best place to start. Notepad would probably work, but s-l-o-w-l-y...

RobF wrote:Is there a way to list what files or parts of files are in the cache?

The cache operates at block-level. You need to use a utility like DiskView for block<->file matching.

RobF wrote:I have plenty of RAM. Should I even bother with invisible memory on a 64-bit OS?

Invisible memory (on a 64-bit OS) means memory outside of Microsoft-imposed limits for your version of Windows (e.g. 16GB for Win 7 Home Premium). Win 7 Pro's limit is 192GB (see Memory Limits for Windows Releases: Windows 7) so invisible memory is only likely to be of use once you've upgraded your system somewhat.

Thanks IM!

I'll run with what I have for a few days and keep an eye on the numbers.

I'm definitely aware that primocache is a block level cache but I'm wondering if there is a way to see what is in the cache. It would be a cool feature if it mapped blocks to files so you could see which files, partial or otherwise, that were currently cached.

as far as preloading the L2 cache I think I'll use TAR and build an archive directed to STDOUT which I then redirect to NUL.
This will read the file and hence populate the cache but the output will be thrown on the floor.

Rob.

RobF wrote:...It would be a cool feature if it mapped blocks to files so you could see which files, partial or otherwise, that were currently cached.

I agree - being able to view what' in the cache and how often it has been accessed would be a neat feature, especially if you could mark individual files to be preloaded in future. Hopefully Romex will consider such things once all the basics are sorted.

Such feature has already been under consideration. Thanks!