(beta 0.7.2) I typically test the FancyCache beta with a size of 28 GB (32 GB system total) on a non-system drive with a process that does a lot of temporary work with large (2+ GB) files. The temporary files are usually (but not always) deleted after the process is complete, so I gain a tremendous benefit from the amount of "trimmed blocks" that do not actually need to be written through to the physical drive. As such I use high latencies (600 seconds or more depending on how long I suspect the process will take) which essentially turns FancyCache into a virtual RAM drive (without the downside of having to pick-and-choose what files to load onto the RAM drive first manually).
So far (for the past two months or so) this has been working spectacularly (on 2008R2), with one caveat. I sometimes grossly underestimate the amount of time the process will take to complete, so the (e.g.) 600 second write cache flush is triggered in the middle of the process, which slows everything down tremendously and isn't useful in any way, since the written data is very likely to be deleted before filling the cache.
Of course, I can simply increase the latency to an absurd amount and manually flush the cache when I'm finished (which is what I do now), but what would be nice as a convenience is a way to change the latency while the cache is active in case I realize 10 minutes into the process that it will take longer than the initial latency period (I can't stop the cache, change the latency, and restart it because the write cache is still partly full and flushing it will ruin any benefit I hope to get from the trimmed data).
I understand that changing most of the parameters for the cache while caching is active is intractable at the moment for various reasons, but I am curious about the latency -- it seems to me that it might be just a time check that could be changed without resetting anything else.
(also, keeping the settings I had last time I opened the FancyCache main window would be convenient, rather than my having to re-enter the same cache size, enable the write cache, and change the latency every time I am about to run the disk-intensive process.)
Thanks for letting us try the software!
Change latency while keeping write cache
Re: Change latency while keeping write cache
Thank you for sharing your experience and feedback. We'll consider it.
Re: Change latency while keeping write cache
viewtopic.php?f=26&t=1215
If I understand right, you are wanting something like number 5 on the list right?
If I understand right, you are wanting something like number 5 on the list right?
Re: Change latency while keeping write cache
#5 (min and max latency depending on I/O conditions) is similar, but in my case the speed of the I/O to the drive isn't the issue; it's that I know that I have a lot of data in the write cache that I am going to trim in a few minutes (beyond what I initially set for the latency). Thus in my case the I/O to the physical hard drive is zero, but I still want the high latency.
The more I think about it, what I am really after is a checkbox/button that reads "suspend all writes to the physical drive unless urgent" (essentially a toggle between whatever latency I initially configured and "infinite") that can be changed without restarting the cache.
The more I think about it, what I am really after is a checkbox/button that reads "suspend all writes to the physical drive unless urgent" (essentially a toggle between whatever latency I initially configured and "infinite") that can be changed without restarting the cache.
Re: Change latency while keeping write cache
I see what you mean now. I'll add it to the list...
The only thing I question about it is the safty of it. Simply giving users that option could cause major issues later on. You would HAVE to put it under some pro-mode to turn it on. I would even go as far as giving a warnning when someone would turn it on... x.x; Just saying ^^;
The only thing I question about it is the safty of it. Simply giving users that option could cause major issues later on. You would HAVE to put it under some pro-mode to turn it on. I would even go as far as giving a warnning when someone would turn it on... x.x; Just saying ^^;