Ideal Cache Size

I always mean to ask this but always forget to do so.
What is the ideal size for a cache?
Mine is set at 550 on my preferences. Can I increase it?
Answers appreciated.
As some of you may know by now I am not technical so long drawn out stuff about "loblolly15 interspaced by didgumquantitive72 at USLpintap" kinda jargon will be meaningless to me.
Thanking you in advance
"Confused in Mimas"

I clear my cashe daily. Doesnt everyone? In this case, size really is irrelevant.

I like my cash in small bills.

I haven't cleared my cache in well over a year. As for the size, i normally have it around 600-750.

My cash only comes in every other week, but it gets cleared almost instantly.

If you have low bandwidth limits, the cache should be as large as possible.

I keep mine at 1,000MB, because if a little bit is good, then a whole lot is better, right?

Its probably best left at 550. You best results are from balancing your hard drive read speed with your broadband download speed.

The cache has 2 storage purposes, as a local index for your inventory (which has to be redownloaded each time you clear cache) and to store local information about your SL surroundings.

As you move about your computer will first check its hard drive cache, for each object you see it compares a reference with a reference it gets from SL, if they match it draws the object from your hard drive cache, if they differ it downloads the new object info and stores this back to your cache.

If you set your cache to 1000mb it can store a lot more object info and references but your computer then has a gigantic file to read thru before it can compare with SL and draw what you see, so its actually slower.

If you set your cache to 300 the reference file is a lot smaller and faster to read but as it stores less must download more object info from SL, which takes download time and bandwidth useage.

So the trick is to find the happy medium balance between them. LL has found that the average user gets best results with about 500mb

There are also 2 schools on clearing it. Some say to do it frequently, some say don't do it unless you have an issue.

Are there actually any benchmarks on cache size anywhere?

The only time I notice a significant difference is right after I clear it. I've even put it on a RAM drive and it doesn't seem any faster.

This is a really good question!

I've been wondering this myself for years.

i believe it helps with frames and things you have rezzed to your cache..like clothes you wear or anyplace you have been or seen..you get a better rez with it..but as we move to new places or see new things the fuller it gets..once we reach the limit is when we see things missing from our inventory or certain glitches start to show up..

i clean mine when rezzing becomes slower than normal or things start to go missing..
bigger would be better i think..

Part of the problem with big caches is that it's not free to have a bazillion files in a directory. Or even +15k, which is what I have in mine right now with the cache maxed out at 1GB.

As the number of files grows, it's harder for the OS to read the directory and find the right file. If it gets big enough, on some systems, in theory, it's actually slower to read from the SL disk cache than it is to delete something old from the cache, sucking a new texture over the network and stuffing that into the cache. You've got to drag the bits over the network more but the number of files doesn't keep growing.

My PC is sorta mid-range. Nice a couple years ago but showing some gray. I've got about 90GB free and I defrag a few times a year so my disk isn't a mess. I've also got 2GB of RAM so I'm not paging (hard on a different part of the disk) all the time.

As your PC specs go down, having a smaller cache probably makes sense. In particular, how much memory you have and how happy your disk is are probably more important than things like your video card or CPU. If you can move the cache directory to a different drive, that's goodness. Even more goodness if you can also move it to a different controller.

Unless you're having crashes or inventory weirdness, clearing the cache every time really makes no sense to me. This is doubly-true if you generally stay in the same area. It's just more work for your PC and for SL..

Which is simply stupid. They should use the same policy on the local disk cache that they do on the cache they use between sims. They're using Squid. Squid has no reference file, it just hashes the file name and stores the cached file as something like "/var/cache/01/23/45/01234567.html". Checking for the existence of a file, particularly if they do it in a background process, makes the best use of the operating system's file system and internal caching optimizations.

I set my cache to 1GB, on a dedicated hardware RAM disk. And it STILL redownloads textures after I leave a sim and teleport back to it. I can't wait until they go to HTTP for textures so I can stick a full squid cache in front of it.
That's why Squid uses a directory tree, with no more than 256 files at any level of the tree.

I've thought about hacking up the viewer to add another level or 3 to the current cache shrub to make it more of a tree but never got around to it. Seems like it wouldn't be too hard, though.

Has anybody tried it? Do we know if the UUID distribution is even enough to make it a win?

As easy as sprintf(buffer, "%.2s/%.2s/%.2s/%s", filename, filename+2, filename+4, filename);

If not, there's no reason you couldn't hash the UUID. Use MD5(UUID) for the first 3 levels.

my experience has been to raise it until you get a problem (like odd slowdowns) then back off, but I run in pretty limited circles because I know so many people and generally just hang with them

if you get inventory issues where you have to frequently clear cache, I'd actually try upping it first and see if that doesn't help with the neccessary frequency.

if you have banddwith limits definitely go big as you can, and limit your exploring (it sucks I know)

lowering it might help if you seem to have a lot of issues with corruption (should force it to fetch requested items and relplace less used one)

as always ymmv

/me wishes he understood this .....

Handy Skytower

I asked the Resident Geek. He said he didn't know about size, but set mine to maximum (1GB) because we have lots of disk space and fast drives.

He also put the cache on a separate hard drive...which in this case happens to be a four drive RAID 0 array, so it is very fast.

This produced a noticeable improvement in SL performance.

I hope you don't have anything on that array you care about. o_O;;;

Hey, even a klutz like me understands the increased risks of running RAID 0. No...everything on that array is lose-able...video footage, mostly, which is backed up on tape.

I set my cache to 1000 and dropped it on a RAM Disk. Nice and fast. Beats the hell out of waiting on my connection to constantly download stuff, especially since SL seems to be the bottleneck anyway. The only time I have ever gotten more than 200KB/s downloading in SL was when I sat at the corner of 4 different sims (so 4 servers sending me data) in the middle of an infohub. Cache is pretty crucial.

And before you bawww about lack of memory, keep in mind people are willing to pay hundreds of dollars in-game and for hardware to run SL. You can get 8GB of basic, non-blingy DDR for around $160 and never have to worry about memory again.

Is there a PC Ram Disk maker?

The whole purpose of a cache is to hold things that will be reused. If you visit a lot of the same places over and over, you could be making your system work more by re-downloading the same data every day.

Additionally, it seems that it always takes a while for my huge inventory to reload after clearing cache.


My cache is set at 600mb. For me, if I have it less than about 400mb or higher than about 750mb, things seems to slow down inworld. I clear cache only when I have major performance, texture, or inventory issues that will not go away after relogging and/or rebooting the computer.

I'm pretty sure there's ways to make one. If not I would think someone has made a program to do it by now. I'm using OS X which has the function built in.