Enhancing your SL Cache

One of the biggest issues I've seen with SL Caching system besides the fact it doesn't seem like its being used right is lag caused by transfer speeds between your motherboard & hard drive. So I came up with this little idea of putting SL's cache to a ramdisk (a virtual harddrive that exists in your ram) and gave it a shot. All I gotta say is WOW. Talk about a difference. So I feel I should share this with my fellow SecondLifers.

Disclaimer: I am not resposible for any damages to your system due to user neglagence. Following this how-to you accept full responsibility for anything that occurs to your system including but not limited to system instability, system failure (crashes), or system corruption (damage to OS).

Now that the disclaimer is out of the way we can get on with the how-to.

Ok things you'll need:
Windows 2000 or better (this includes WindowsXP, sorry Mac guys)
Windows Server 2003 Resource Kit Tools (linkd.exe)
RAM Disk software (I used RAMDisk XP)
512mb RAM (768+ recomended)

First thing you'll need to do is download the Windows Server 2003 Resource Kit Tools if you don't already have it. LinkD.exe

Now find yourself some RAMDisk software. There are a few free ones out there, but keep in mind we'll need one that allows you to make an NTFS drive. I used Cenatek RAMDiskXP wich you can find a 30 use trial (not bad if you're like me who only resets their computer like once a month). Now once you aquire some RAMDisk software make yourself a RAMDisk using the software you found. Now if you're using 512 - 768mb I'd recomend no more than 50 mb otherwise you hit some system performance problems, 768 you might be able to slide with a 200mb disk. Anything 1 gig or better you can set this to 200 - 500 since you got ram to spare. Now make sure this ramdisk is NTFS formated for best performance. Some RAM disks require you format it with Windows Disk Management before the drive becomes usuable as was my case to get it formated in NTFS. Now once you have your partitioned ramdisk its time to link SL's cache to the ram disk.

EDIT: Here I'm gonna tell you where to get RAMDisk XP and how to configure it.
Ok, first download RAMDiskXP here. Once downloaded and installed we're gonna make a ramdisk. When you first start up RAMDisk you'll see how simple this is gonna be. Where it says Disk Size enter the size of the cache you intend to use. Choose Unformatted and hit start RAMDisk. Now the drive won't be ready until you format the drive. To do that you'll need to enter Windows Disk Management. To do this goto Start -> Run. Enter "c:\windows\system32\diskmgmt" and hit enter. This will load up Disk Management. BE VERY CAREFUL HERE NOT TO DO ANYTHING BEYOND WHAT I'M INSTRUCTING YOU TO DO OTHERWISE YOU COULD RUIN YOUR SYSTEM. In the lower half of the window you should see partitions. You wanna look for the unpartitioned space on a seperate disk (note Drive C will be Disk 0, D Disk 1, etc.). Assuming you only have 1 harddrive then you will be looking for Disk 1. Right click on the empty space and choose Format. You will be prompted to assign a drive letter (I recomend Z). Make sure you choose Primary for the partition type. After you are done formatting exit Disk Management and the ramdrive should appear in your My Computer list of drives. Congrats you've created your RAMDisk.

Now you must clear your cache and delete whatever wasn't cleared from the SL Cache director (usually found in c:\document and settings\<username>\application data\secondlife\cache where <username> is the name of the account that has SL installed). Now once thats cleared make a directory named cache on your ramdisk. Now here's another fun part: goto the command prompt. Start -> Programs -> Accessories -> Command Prompt for those who don't know.

now enter the following command (note this is assuming Z: is the drive letter you chose for your ramdisk, Change Z: to your drive letter. Replace %USERNAME% with the propper username that has SL installed):

C:\Program Files\Windows Resource Kits\Tools>LinkD.exe "C:\Documents and Settings\%USERNAME%\Application Data\SecondLife\cache" "Z:\cache"

There, everything should be linked and fully operational. Enjoy the speed boost.

EDIT: keep in mind most RAM disks will be wiped clean apon system reboot. Some have the option of saving the ramdisk on shutdown/reboot. Unless the one you find has that option then I recomend you turn it on unless you don't mind recaching your inventory every reboot. Also each ramdisk is different wich is why I didn't go too indepth. I just whipped this up real quick for the tech savy amongst us to give it a whirl. I will do a reversion later on with a bit more detail using the ramdisk software I used.

Not sure how that works so Im just speculating here...

Seems like it would speed up an SL session, but if you exit SL and or reboot your machine will you have to build up that cache all over again?

Seems like it could be good for people that tend to log in for extended periods if the above is an accurate guesstimate. But if you relog and reboot a lot it may actually take longer to re-cache all the time.

For me Im in SL for like 5+ hours when I do get a chance to log in, soseems like a good idea. I'm def. looking into it, Thanks for the heads-up Ron

No you only loose your cache if you reboot your machine and your ramdisk software doesn't have the option to save your ramdisk on shutdown. If your software, like mine, allows you to save the ramdisk on shutdown you'll never have inventory recaching issues. But most out there don't have that option. So the only ways you'll loose your cache is if you A) force clear your cache within SL or B) restart your system. Honestly clearing the cache every so often is probly healthier for your system anyways since SIMs are so dynamic you'll probly have excess textures just taking up space in your cache after a while.

Seems like a good idea for me, considering I rarely reboot my computer. Anyone have any ideas on getting this to work on OSX? There are several RAM disk programs out there, but what about setting SL to use it as your cache?

A RAMdisk is a piece of software that creates an artificial 'disk' that exists purely in memory. Becuase it exists only in memory, it is generally orders of magnitude faster than a physical disk could ever be.

The benefits of a RAMdisk are obvious - sheer flat-out speed. There are downsides though, the biggest one being that for every MB of space you reserve for your RAMdisk, that's one MB of memory you have available to run software. Also once the power is turned off, *poof* - all contents of the RAMdisk is gone.

This RamDisk XP sounds interesting though, and SL's cache sounds like a prime candidate to benefit - will definitely be checking it out!


- Newfie

Wow, what a cool idea, and also probably good for the machine; less hard disk use = less heat generated. I'm going to look into this and see how it can be easy maintained across reboots!

Thanks!

-Flip

After a little searching, I found the following free ram disk software for OSX. I'll give it a try tonight and see how it goes.

http://www.macupdate.com/info.php/id/16518

I second the request for OSX support.

NT/XP already does a lot of predictive caching. You're not going to find too much of a speed up over just having lots of ram.

This sort of thing is useful for stuff that you want to load up quickly that you have not been using for the last little while.

For example, if you've been in SL for an hour and then you want to load up photoshop real fast.

Whoa, are you serious about the performance improvements? AFAIK, SL is supposed to use as much RAM as you've got... and only hit the disk cache if its not in memory yet.
I guess if the disk access is slowing things down maybe the cache should be disabled altogether.

SL is suppose to use as much ram as possible, problem being it really doesn't. From what I've seen it uses around 350mb at best. Out of the 1024mb ram on my machine, if all I have is SL + WinXP + Trillian + Firefox running (wich is normal for me), my system doesn't use more than 650mb of my available Ram. Honestly LL should add in a feature to load more textures into ram for machines that have more than 512mb of ram instead of caching it to the hard drive. If they do this there's no need for the ramdisk.

If any application that uses a cache works better if the cache is in a RAM disk than if the cache is on disk and the RAM taken up by the cache is just used for the program itself, then there's just plain something wrong with that application.

Just buy a IRam.

I'm not sure how much this actually helps SL run on MacOS X, but if it does there is no additional software required! Everything you need to make a ram disk is built right in.



Step 1: Determine the size of your ram disk (in sectors, sector size being 512)
number of sectors = (MB RAM desired) * 2048
50 MB = 102400
200 MB = 409600
500 MB = 1024000
1000 MB = 2048000

Step 2: Open Terminal.app and switch to superuser (you must be logged in as an administrator to do this)

computer:~ user$ sudo su -
Password:
computer:~ root# 

Note that the password you enter here is your administrator account password, not the root password if you have the root account enabled

Step 3: Create the ram disk

computer:~ root# hdid -nomount ram://102400
/dev/disk1                                             

Here I'm creating a ram disk with 102400 sectors (enough for 50 MB). Change this to correspond with the Disk Cache Size Second Life is set to use.

Take note of the name of the device that is created (disk1 in this example)

Step 4: Create a filesystem on the device

computer:~ root# newfs_hfs /dev/rdisk1
Initialized /dev/rdisk1 as a 50 MB HFS Plus volume

Here I specified rdisk1 which corresponds with disk1 - the device which was created above in step 3

Step 5: Mount the volume

computer:~ root# mount -t hfs /dev/disk1 '/Users/user/Library/Application Support/SecondLife/cache'

Here I mount disk1 at the location of the Second Life cache directory. The username I play Second Life under is user in this example, you will need to change it to the MacOS username you play Second Life logged in as.

----

That's it, your Second Life cache directory is now stored on a ram disk, whatever that's worth Probably the easiest way to revert everything back to normal is just to reboot.

you can mount drives as directories in windows too (though nobody does, since it's basicly just a junction (symbolic link) that uses the hardware address instead of a drive letter).

IRam type devices have been around for a good long time. You can also boost read speeds by using a striped RAID array (this is why RAID was invented; old drives had slow access rates, but when stripped they could distribute the load).

Also just a slight reminder that in XP, 2000, 2003 most errors occur due to ram issues. By putting more things into ram you run a higher risk of incuring these issues. Hence why you do not get blue screens of death and the like nearly as often.

Personally if you need more speed out of your harddrive for SL I'd look into a scsi, raid, firewire, or that new conenction (name evades me right now). Place cache in there and put no other harddrives on the same connection.

Not all of us can afford to toss in new hardware for SL. I myself don't have a SATA capable motherboard nor do I have RAID available. This way is a cheap fix nothing more. Honestly I have yet to get WinXP to blue screen on me, probly a combo of luck and good maintance to my system. So far I have yet to have any issues.

It rarly blue screens but that is because most blue screens in 9x, ME are caused by system resource which is directly related to your RAM.

Thats because XP & 2000 are NT based. NT has a much better grasp over memory management because it has to be able to remain stable enough to be used as a server platform and/or professional desktop platform. So if anyone is bluescreening XP they're doing something wrong.

I just bought 2GB of ram (from the 512MB) I had originally, and SL is much smoother, especially flying.

I like the Ramdrive idea, but it steals available ram from all programs.

Since my PC has slots on the front for various memorycards (such as SD Ram, Sony MemoryStick) etc..., what are the thoughts on setting the SL Cache to a maybe a 1GB SD card?

Access to a memory card must be quicker than a spinning hard-drive (right??). Cards are pretty cheapish. I've not looked into the different cards to see what access times are

Now where to change the default directory.


> OK, bit of an edit before I post. I had a quick look at FutureShop.ca, a 7200RPM HDD says 133MB/sec transfer with a 9.3msec seek time. A 'fast' SD card only says 20MB/sec transfer, so either I'm reading it wrong or the HardDrive is 'much' faster than memory.

A HD is much faster then removable memory sticks. Trust me, you have 2.5 gigs of RAM.. do you honestly think you're gonna be utilizing all of it? Even if you were to make 512mb of that into your SL cache, you're still gonna have 2 gigs free for everything else. Plus no one said you had to have it active all the time, only when you're playing SL. (My software allows me to shut down the drive and turn it back on when needed without rebooting.)

Heh. I think I realized I was speaking out of 'behind' when I checked the speeds. I had figured that Hardware Memory would be much faster than something that spins and needs to be accessed, but there's obviously much more to it than that

I'm going to have a play with this when I get home and maybe utilize some of my 2GB.

Ron, just checking, and I'm pretty sure that SL automatically does this, but do you know about and have enabled that feature in your Preferences that tells SL you have >=512MB of RAM?

Yes Eggy I do have that enabled. I still saw a big improvement using this ramdisk method.

Sounds like LL has work to do on their memory management. If you have 2GB of RAM and you tell it to use 2GB, it should use all that 2GB before it even thinks about putting anything in a disk cache.