Best filesystem for multi-OSes host.

Discussion in 'General Questions' started by cpl593h, Sep 20, 2006.

  1. cpl593h

    cpl593h Junior Member

    Messages:
    16
    Hello,

    I've bought an high-end machine, on which I plan to use Parallels heavily (with at least one VM under Linux, which will replace an old real test server and another one using Windows 2000 SP4, which should do a good job at sandboxing some Windows app I need).

    I plan to use the _same_ virtual machine file under Parallels Desktop (Mac) and Parallels WS (Gentoo Linux and maybe some kind of Windows, XP or Vista).

    In the absence of direct hard disk support, I'll have to use a host filesystem for my VM HD files. The only problem is that VM HD files are typically 4GB+, which rules out FAT32 as a VM HD file host. FAT32 is AFAIK the only filesystem that's readable by OS X, Linux and Windows.

    Another solution would be to use an HFS+ non-journaled partition, which is supported by Linux and may somewhat work on windows using Macdrive.

    None of those solutions are perfect and I wonder if someone here can suggest me a better idea. _Maybe_ there should be an option for splitting VM HD in 2 GB chunks?

    Another possible scenario: I make a big 600 GB image, on 3 200GB hard disks and a micro-Linux distribution which just serves as a Samba server. All my OSes will be able to access my data, I'll be able to use a good, journaled FS (probably Reiser3). But is there an option for me to span an image on several HDs?

    Ideas?
     
  2. joem

    joem Forum Maven

    Messages:
    1,247
    I'm a little puzzled over what you are trying to do. Do you mean the same physical VM file accessed by two host machines? Or do you mean a copy of the file? If you try to use the same file, then one of the guests will be accessing its HD over a network, which will probably slow it down substantially. If you are using a copy, it doesn't matter what the host filesystem OR the guest filesystem is as long as the host can read the host disk, and the guest can read the .hdd file. You can copy the .hdd file from one host to another no matter what filesystem is in use on either host.

    If you need a guest disk larger than your chosen filesystem can handle, (32 GB per disk for FAT32 with a limit of 4GB per file), you can attach several (up to 3 with a CD, or 4 without) .hdd files to your VM. If you are using Windows (2000 or XP), NTFS is probably the best choice for the guest disk format. I see no reason to use anything else, because the guest will be the only one reading it. To move it or back it up, you just use host tools to copy the file, which is just packed binary junk to the host.

    What am I missing?
     
  3. David Corrales

    David Corrales Hunter

    Messages:
    189
    There's a driver for ext2/3 that works in Windows and supports it fully. I'd recommend that filesystem since Mac, Windows and Linux can read/write.
    Link: http://www.fs-driver.org/
     
  4. cpl593h

    cpl593h Junior Member

    Messages:
    16
    I know what you'll read will sound crazy. It probably is, and I reckon I'm asking for trouble here : I'm basically trying to replace four machines with a single one, mixing dual/triple boot and Parallels. Half the reason is I need it, the other half is that I want to test if it is possible.

    I used to have four machines for multiple OS web development testing (each had its own OS, because I like diversity as much as using the best tool for the best job). I plan to be moving a bit in the year to come, so I'm getting rid of the four aging machines and replace them with a single Core 2 duo machine (not sure which one, doesn't matter at this point).

    I'll double or triple-boot the machine, which will have three S-ATA disks. Each of them will have ~20 gigs for the OS and apps so that I don't have to play too much with bootloaders -- I'll probably use an USB or floppy bootloader and let the OS use the MBR as it wants. The rest of each disk (~230 gigs each) will be for data.

    I plan to use the same Parallels VM's on each of those OSes (that shouldn't be a problem), one of the VM's being a basic LAMP setup running on Gentoo (for which I had a dedicated machine until now, but which works very well -- even better -- as a Parallels VM demo VM on a P4).

    Now, the problem is how I'll access my data. As stated above, I'll have ~690 gigs spread on three partitions. Since no good multi-OS FS is available (FAT32 has its shortcomings, I don't trust NTFS support on Linux and I'm not sure the Win32 ext2 driver will be stable enough, especially under Vista's RCs), I plan on doing what I've always done, using a dedicated server to store my data, so it is accessible by each OS and each VM, probably through SMB.

    Except that I won't have multiple PCs anymore. So I thought I'd try to virtualize the file server too and use my LAMP VM as a file server, running Reiser3 internally.

    Since Parallels has no support for direct partition access, I'll have to create virtual hard disk files on my three 230 gigs partitions. And here is the problem I tried to explain yesterday : what filesystem will I use to host those 3 images ? The only candidate is FAT32, but it would require hard disk images to be stored as split files (230 gigs = 58 FAT32 files, or 154 files if we consider I'll have three disks). I don't think Parallels allows that, and the slightest file corruption will lose all my data.

    I don't really think that I'll use such a complex setting, since it is really asking for trouble. Maybe someone here will come with a more sensible solution.

    Sorry for the long post. Feel free not to answer :D

    PS: if anyone wonders why I want to dual boot, the answer lies in two words: eye candy. The machine will either be a PC or a Mac Pro and I want to play with Xgl / Aero / maybe Aqua.
     
  5. constant

    constant Forum Maven

    Messages:
    1,010
    .
    What about shared folders?
    .
     
  6. cpl593h

    cpl593h Junior Member

    Messages:
    16
    I don't think it would work. Aren't they for windows guests only?

    Moreover, it doesn't solve the fact that if (say) I'm on Linux as my primary OS, it won't read my NTFS
    HD image (or it will read only, or with the far too much experimental Captive or User-Mode NTFS).
     
  7. joem

    joem Forum Maven

    Messages:
    1,247
    Sounds to me as if you can easily get it down to two machines: One core duo or core 2 duo (or dual core 2 duo), multi booted with your various OSs, and one relatively low performance machine on the network as a file server, maybe using gigabit ethernet between them. Maybe one of your old machines with new disks would serve (pun intended) the purpose. This still has you buying only one new machine, and getting rid of three of the four.

    Note that for testing, there is enough difference between the core duo and core 2 duo that you may need both, depending on what you are testing.

    Sounds a bit more practical to me.

    Have fun.
     
  8. cpl593h

    cpl593h Junior Member

    Messages:
    16
    First of all, thanks for your answers, they helped me thinking of the best strategy and to choose my hardware wisely, even if I'm still not 100% decided.

    Anyway, for practical reasons the second machine is an option I'd rather avoid, especially for noise, power consumption and heat reasons.

    I think I will use some kind of FAT32 native support, until Parallels support direct partition access. Then using three NTFS/Reiser3/ext2-3 'real' distinct partitions, native for the system(s) that support it, or served through a VM for those that don't, looks like a good compromise.

    I know that native partition support is planned, anybody has a ETA?

    Thanks
     

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