Some suggestions on strategies

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Manny
Level 6
Level 6
Posts: 62
Joined: Tue Nov 13, 2012 11:42 pm

Some suggestions on strategies

Post by Manny »

Some suggestions about cache strategies
I'm using SuperSpeed SuperCache similar product on my personal pc's and on production servers for a year. It really helped me.
But their product seems to be dead, so i look forward with FancyCache.

So at first what i did really miss in FancyCache.
1) Changing settings on the fly.
for example
1a) when i need to move or copy large amount of data between partitions on same hdd i move all available ram to cache, then hdd only read all amount to ram, and then writes it as single queue to new place, i think no need to explain how much it faster them to move hdd heads all th time
1b) same benefits with defragmentation and vmware disk compaction
1c) when i lunch something heavy, i just decrease cache size to minimal - 512mb per partition
so in general i change cache setting 10-20 times per day

2) Pagefile caching. Usually it saves my brain cells when some app start to use about 1-2gb of page file... In this case everything works so slow that i want to make hardreset, but because pagefile is cached i can manage to open SuperCache and free up some memory.

Now what i really want to see in new versions of cache software.
1) Dynamic size, yeah that one you have for ram drive solution, so i can specify Low and High limits. So for example for system partition 512mb - 1.5GB. For VM's partition 512mb - 4GB. Then i would not need to change cache settings all the time, because this is pretty annoying :)

Not very important, more like votes to other users suggestions and ideas:
2) Persistent L1 cache - no need to explain
3) Load on system kernel boot - boot speed up in general
4) Interaction with NTFS cache and SuperFetch
5) Cache Whit List - add some files to cache on persistent basis
6) Something similar to NCQ, i don't know may be it is in place right now when Deferred Write is enabled, but in general when we have some changes in memory, we can reorder blocks write queue
7) Cache slowest blocks first - it is not a secret that hdd some times does remapping, and such remapped sectors sometimes are very slow, it would be cool to keep them always cached. For example Victoria marks such sectors when access time more then 500ms, when good sector has less then 10ms access time. It will eliminate systems hangs on iowait to that sector.
8) Some more statistics about cache usage, basically i want to know how many active blocks in cache.
Let think that Cache is the table with three columns:
Address
Data
HitsCount
So i would like to perform such query "SELECT HitsCount, count(*) FROM cache GROUP BY HitsCount"
And build a chart in exel, and then i can make decision to increase or to decrease cache size. Because right now it not very obvious what size is the most effective.

If you ask me to compare performance of SpeedCache and FancyCache. I would say that have very different fetch and write strategies.
Some times FC works better, some times SC. SC works better in complicated scenarios, for example right now i'm installing 90 windows updates, and SC with deffer write (60s) keeps my hdd cool, but FC produce 100% hdd load on same configuration (Disk + Read/Write + Deffer Write 60s). But when i reboot in second time my VM with windows XP, with FC it boots in 3-5 seconds, but 25-30s with SC.
Also i think that deffer write works a bit different in SC, they do not really keep all data in memory for the timeout, they start to write it immediately, but they guarantee than no data will be stored in ram longer than that limit. So they have two threads, one writes to ram, second one writes to hdd, and when seconds one have to much work(have data which reached the timeout), first one freezes and wait seconds one.
I'm telling that it is 100% true, but it seem like that for me after 1 year of usage.

Thank you for your great work, you made very nice product. Good luck!
Feel free to ask question or say "fuck off man" :D
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Support
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Joined: Sun Dec 21, 2008 2:42 am

Re: Some suggestions on strategies

Post by Support »

Thank you, Manny. Lots of suggestions! We'll consider them. I think some are already mentioned by other users and some not easy to be implemented. Anyway we are still improving Fancycache for better performance and features.
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