A register article today was talking about how MetaRAM can now get 288GB of RAM in a single machine. As someone quickly pointed out in the comments, Sun Microsystems have a machine out for almost 2 years now which supports 256GB of RAM. Its an x86 machine called the x4600. Sun also sell a SPARC machine called the M9000. It supports 2TB of RAM. Thats 2000GB of RAM. Oh, and its got 64 processors.

People should really not be surprised that the limit of how much RAM they have, is not to do with their choice of hardware, but rather choice of Operating System. At this time of writing, thew most advanced version of Windows Server 2003 (Datacenter Edition) CAN address up to 2TB of RAM. But because its written for the x86 architecture, you’ll struggle to run it anywhere to address it all. I should imagine that its partly to do with market demand; you can be sure that if customers were crying out for high capacity x86 equipment, the manufacturers would be making it. Maybe Microsoft should make a port of Windows to run on SPARC?

I find that on the whole this is quite typical of Sun. Their hardware can cost more, but it comes out earlier, and its better than kit in the same class. Sort of like Volkswagen or BMW. Higher cost, but higher quality, and more innovation.

We make the files (we can use files instead of real disks…):

anton@solaris-devx ~ $ mkfile 100M /tmp/file1
anton@solaris-devx ~ $ mkfile 100M /tmp/file2
and then su to root to make the ZFS file system (mirrored):

# zpool create crazedPool mirror /tmp/file1 /tmp/file2

I should note that for some reason ZFS didn’t make use of the entire file size:

# zfs list crazedPool
NAME USED AVAIL REFER MOUNTPOINT
crazedPool 110K 63.4M 20K /crazedPool

And now the real test. How about a big file? Lets say, 100G?:

anton@solaris-devx dir1 $ time mkfile 100G woot
real 1m21.995s
user 0m0.191s
sys 0m30.308s
And what about 10000 files, each 10M in size?:
anton@solaris-devx dir1 $ i="0"
anton@solaris-devx dir1 $ time while [ $i -lt 10000 ]
> do
> mkfile 10M la0$i
> i=$[$i+1]
> done
real 1m46.789s
user 0m4.665s
sys 0m43.492s

So far, so good. So now lets push the envelope off the desk. Or maybe off a cliff. Lets see what happens when we make a 100TB file with ZFS!

anton@solaris-devx dir1 $ ls -l megaFile
-rw------- 1 anton staff 107374182400000 Mar 15 18:05 megaFile

and the compression ratio?:

anton@solaris-devx tmp $ zfs get compressratio crazedPool
NAME PROPERTY VALUE SOURCE
crazedPool compressratio 1.00x -

hmm, not quite what I was expecting!

Furthering the idea of putting the disk install image in RAM before installing, why not write to a Virtual hard drive, also in RAM (if your using VirtualBox)! Specify /tmp as the prefix to your disks name in the “Virtual Disk Location and Size” dialogue window. The result? An installation of windows that will reboot in about 15 seconds. Of course, this is good for some tasks, but not all! Your millage will vary!

NOTE01: I would recommend your have at least 3GB of RAM before trying this!

NOTE02: If you want to keep the install for good, you will need to copy it off /tmp before you reboot, otherwise your virtual drive will be gone!

I must admit though, it still wont solve any post-install issues!