8 replies to this topic

[spencerforhire]

I have a bunch of sample dd images and I've had good luck so far with ImDisk seeing (or maybe I should say searching for... I've been letting ImDisk locate volumes itself) and mounting NTFS and FAT32 volumes inside them. I was wondering what other filesystems ImDisk works with?

[Olof Lagerkvist]

I have a bunch of sample dd images and I've had good luck so far with ImDisk seeing (or maybe I should say searching for... I've been letting ImDisk locate volumes itself) and mounting NTFS and FAT32 volumes inside them. I was wondering what other filesystems ImDisk works with?

Short answer: The filesystems that your Windows OS supports.

ImDisk is at "disk driver" level, filesystems are handled by filesystem drivers above the disk driver on the device stack. Any filesystem driver you install in Windows could be used with ImDisk drives.

Some filesystem drivers that could be of interest:
http://www.fs-driver.org (ext2)
http://www.softmosai...roduct-1577.htm (also ext2, but not freeware)
http://ufs2tools.sourceforge.net (ufs)

[deroby]

Bit late in the conversation, but I seem to be running into an issue with ImDisk (great stuff btw!) when trying to run MSSQL Databases on it, and IMHO it's relevant to the question being asked. If ImDisk works 'below' the FileSystem level, might it somehow cause the FileSystem to behave differently ??

More specifically, I'm doing test-runs for MSSQL 2008, running stored procedures on a RAM-disk mounted by ImDisk.
This works pretty much for everything and is a LOT faster than running this on my old laptop's HDD, however, it fails when trying to do a so-called snapshot of a database.
The error thrown is :

Msg 1823, Level 16, State 2, Line 1
A database snapshot cannot be created because it failed to start.
Msg 5119, Level 16, State 1, Line 1
Cannot make the file "R:\filename.ss" a sparse file. Make sure the file system supports sparse files.
Msg 50000, Level 16, State 1, Line 97
Error while creating the snapshot

When I run the same tests from my 'spinning disks' drive, everything works just fine.

As far as I know I've not done anything different on the RAM-disk based R:\ versus my 'spinning disks' d:\, both are formatted using NTFS on Windows7, both *I THINK* using 4096 for cluster size.

Either the error in MSSQL is wrong or misleading, or there must be something I'm not doing right here... any tips ?

Much appreciated.

[Wonko the Sane]

@deroby

Cannot say if this is the case, but IMDISK is NOT at the same "level" of a "real" hard disk, actually it does not make a "disk", but only a "volume" (or "filesystem").
Read here:
http://reboot.pro/13...350#entry122350
AND given links.

You may want to try another ramdisk driver with a "lower" level, such as Firadisk or WinVblock, but they are slower than IMDISK.

Another one to try (as long as 4 Gb is enough) is this one:
http://memory.datara...oftware/ramdisk



Wonko

[deroby]

@Wonko the Sane

I followed the links but got kind of 'scared' by the technobabble there =) Had a look at the DataRam thing and hold & behold, it seems to be able to do the Snapshotting thing of MSSQL. To be honest I had never heard of it before, and although it indeed is slightly slower than ImDisk (ca 10% for my use-case) it still is a lot faster than doing this on my regular disk, bigtime !

Thanks for the tip(s) !

(I'll keep watching this page to see if there might be an ImDisk solution too, but for now I'm actually quite happy with my error-free logfiles =)

[Wonko the Sane]

(I'll keep watching this page to see if there might be an ImDisk solution too, but for now I'm actually quite happy with my error-free logfiles =)

You can also test some of the other RAMdisks available, the "full list" is here:
http://reboot.pro/1507/

If my hypothesis is right, using no technobabble , the kind of ramdisk driver that will work is that (those) that you will be able to see in "disk management" once installed/running.

Among the "in house" drivers, IMDISK is definitely faster, but both Firadisk and WinVblock are under development and may soon "catch up" :
http://reboot.pro/13863/

And there are faster than IMDISK ramdisks, too
http://reboot.pro/10637/
though results of the above seem contradicted by previously mentioned more recent test )


Wonko

[karyonix]

Cannot make the file "R:\filename.ss" a sparse file. Make sure the file system supports sparse files.

If your R: file system is FAT, try NTFS.

[Wonko the Sane]

If your R: file system is FAT, try NTFS.

As far as I know I've not done anything different on the RAM-disk based R:\ versus my 'spinning disks' d:\, both are formatted using NTFS on Windows7, both *I THINK* using 4096 for cluster size.

Wonko

[deroby]

Quite the list =)

Well, going through them diagonally it seems that
* I have quite a different "usage" for my ram-disk than you guys (mounting & booting and installing from images ??? )
* The DataRam thingy seems to be a reliable piece of software (**)
* Maybe I'll give SuperSpeed ramdisk another look as it seems to be dummy-proof too, but as for now DataRam will have to do, and I can always revert to ImDisk if I need the extra speed and simply strip the Snapshot lines out of the test-scripts (if any).

Thx & good luck with all the Ramdisk development going on here, it all looks quite impressive but way above my level.


Cu
Roby

(**: although I'm under the impression that it taxes my machine more than eg. ImDisk, even when not using it. Having it autoboot as an empty NTFS disk is kinda good and bad, luckily the empty image compresses to 70Mb on-disk, loading close to 1Gb during boot sounds horrendous =)