5 replies to this topic

[Yorn]

Suppose I wanted to use space network space and create image files. What software would be best for this if I intend to also use IMDisk to mount those drives. I'm looking for what would be the most efficient.

Specifically, I have a copy of Windows Home Server running on one computer. The intention is to install IMDisk on this computer and then create image files of varying sizes on spare computers throughout the home. These would be mounted as drives, and Windows Home Server has a unique service called "Drive Extender" that is like a software RAID where you can dynamically add and remove drives. I figure that as long as one drive never fails (or only one computer is ever turned off) I'll have a large amount of space.

Anyway, all I'm asking is what is the most efficient drive image to use with IMDisk, both from a CPU usage and network bandwidth usage standpoint. Thanks.

[was_jaclaz]

IMDISK supports only one "format" of drive images, i.e. RAW ones.

A RAW image is a byte per byte copy of a hard disk or of a partition.

NO optimization of any kind, exception made, IF they reside on a NTFS partition, to be created as "sparse" file, i.e. a file that has a fixed "external" size, but that actually occupies on hard disk only the minimum size needed for the filesystem files and for their actual contents.

If you use VDK, you can, besides RAW ones, also use VMware format images (.vmdk) that can have some interesting features (like growable images and multi-volume ones), but that of course have a slightly lesser compatibility.

Images can be converted from RAW to VMDK and viceversa with the qemu-img.exe

IMDISK is a "Virtual Volume" or "Virtual Partition" Driver, whilst VDK is a "Virtual Disk" Driver, and thus allows for seeing the mounted drive also as "Physical Drive", besides "Logical Drive".

IMDISK expects to find at sector 0 of the image the bootsector (but you can use the OFFSET parameter to mount a Volume that is anywhere within the image), VDK checks the contents of sector 0 and, if it is a MBR will mount correctly the partitions in it, or, if it is a bootsector, will mount directly the volume.

I don't know if this "Drive Extender" operates just on Logical Drives or it needs to be interfaced to the Physical Drive, if the first, both drivers may work as well, each with it's own peculiarities, if the latter, only VDK may work.

jaclaz

[Yorn]

Okay. So it sounds like the only images it can mount are .VMDK and .RAW? I'll just use the VMWare option, but it will be accessed via a Windows share, so I can report if I have any problems. Sounds like qemu-img.exe is the answer to the original question I had, so thanks for answering that!

[Yorn]

Okay, now I'm having problems with devio. I'm trying to mount a drive remotely and all I see in the control panel is options for loading a local image. How exactly does the link between devio and imdisk work? I tried doing a search on the forums and got a timeout, so if this has been covered before please just link me to the request. I'll keep trying to search, I'm sure someone has asked this before.

[Olof Lagerkvist]

You can use the command line tool imdisk.exe to mount remote images through devio. Example:

imdisk -a -t proxy -o ip -f 192.168.0.10:9000 -m R:

This will connect to devio on port 9000 on IP address 192.168.0.10 and mount the volume as R:.

Anyway, I doubt that it will be possible to use ImDisk volumes for a RAID in the way you want here, but it is of course worth a try.

[Yorn]

Yup, you're absolutely right, I can't use it the way I was hoping to as the drives don't show up as JBOD (just a bunch of disks) in Drive Manager. They have to show up as actual devices in order for Windows Home Server Drive Extender to pick them up as a location to add files to, I think. I did find that command though, and it works good. If anything, I can maybe do backup drives or something. It'd be nice if I could use all the networked drives as ONE drive, but then that'd just be a single point of failure, where if any one drive wasn't connected, the whole thing would be junk, and I don't want that at all.