virtualbox.org

VirtualBox v4.3.12
Guest Additions installed
Host: Win 8.1 x64 (16G RAM)
Guest: CentOS 6.5 x32 (2G RAM)

Hello. Query, is there a way to install a guest OS with multiple partitions spanning seperate Host disks, particularly one SSD and one HDD, while being able to make snapshots and have the snapshots directed to the HDD?

My issue is that the Guest fails to operate after a snapshot is taken. I want to be able to have my Guest VM on seperate partitions on seperate Host disks. Both Host disks (SSD & HDD) are dedicated to VMs. I am having trouble getting this to work for my Linux guest. I would post the error, but I deleted the Linux VM because I was about to try again with different VHD attributes (Virtual Media Manager) and also try to see if a linked-clone would help, but I thought I would try here instead and maybe save myself a headache. Searching the error code led me to nothing relevant.

The reason I am asking if this is even possible is because I want to take advantage of the higher I/O of the SSD on my VM system partitions, so when I run multiple VMs there is less lag time. I do not want to use up the SSD as storage; that is what the platter disk is for. Also, I want my snapshots on the HDD, not the SSD.

My procedure was as follows:
1. Change VirtualBox default to the SSD
2. Create VM without disk (places .vbox & .vbox-prev in default folder)
3. Create system VHDs in default location (SSD)
4 .Change default location to HDD
5. Create home VHD (HDD)
6. Adjusted VM settings
7. mounted install ISO and booted up

(1st) Installation went fine and the Guest ran flawlessly while I installed Guest Additions, Updates, and a few pieces of software. After the snapshot was taken The Guest failed to load. Furthermore, loading the snapshot and deleting the snapshot both failed.
(2nd) Then I tried again with the same steps except I created the home partition before I changed the default location (steps 4&5).
(3rd) Then again with the default folder located on the HDD (step1), so that the .vbox & .vbox-prev were on the same drive as the intended snapshots and finished off as I did the 1st install.
(4th) Once more with the default folder located on the HDD (step1), but this time I finished off as I did the 2nd time.
I am a stubborn individual that can usually find my answers through Google, but all I could the find the past couple of morning/afternoons were dozens of posts regarding moving existing VMs or creating multiple partitions within the VM and a couple on multiple Guest partitions on seperate Host drives (most were very old posts), but nothing concerning the latter with a specific location for snapshots. If I missed something a link would be much appreciated.

Linux guest setup desired:
VHD (fixed) -- no LVM
sda/boot 256 MB (host SSD)
sdb/tmp 768 MB (host SSD)
sdc/SWAP 1024 MB (host SSD)
sdd/ 5120 MB (host SSD)
VHD (dynamic)
sde/home 256000 MB (host HDD)
OR
VHD (write-through dynamic or shareable fixed) -- dont really need a snapshot of /Home
sde/home 256000 MB (host HDD)
* I choose VHD because if I need to extract any data, it is easily done by mounting the VHD in Windows Disk Manager. If VDI is a solution then I can change.

I was also considering a linked-clone, but was unsure if that would solve my problem. If I understand it correctly if I follow my steps then make a linked-clone to the HDD then only new changes will be placed on the HDD and my system partition will still reap most of the benifits of an SSD and snapshots will be made of the clone on the HDD. However, I have not tried that since the idea just popped into my head this morning after reading posts and I have to get to my job search. Later tonight I might try this, but I thought I would give a cry for help a go first.

Thank you in advance for reading my WOT and I hope I am not making someone shake their head at my ignorance at what may be an obvious answer. Any relevant help would be gratifying.

micnip wrote:Thank you in advance for reading my WOT and I hope I am not making someone shake their head at my ignorance at what may be an obvious answer. Any relevant help would be gratifying.

Not your ignorance, but your ability to write such a complete list of your actions and yet NOT providing the error message, making your WOT useless
Also please read Minimum information needed for assistance and provide the zipped log file as an attachment and the guest settings.

Apologies on not supplying that info from the start. I sat down and recreated the scenario with the same steps previously mentioned. I only reinstalled twice since the error codes were identical and the 1st install is my preferred method. Moreover, below I added a few items that I didnt have listed to my previous list. However I did skip the software installations to save on time. I figure that should have little to do with my problem. I also attaches a zip with my log files; there were three so I included them all.
I forgot to add that I changed the Snapshot Folder location. There should be a step 4.5. After I changed the default location to the HDD I changed the Snapshot Folder to the same location.
Furthermore, for reference my Directories are as follows:
SSD:\VirtualBox\CentOSx32\
HDD:\VirtualBox\CentOSx32_home\Snapshots

errorCode:

Failed to open a session for the virtual machine CentOSx32-01.

No error info.

Result Code: E_FAIL (0x80004005)
Component: ProgressProxy
Interface: IProgress {c20238e4-3221-4d3f-8891-81ce92d9f913}

Thanks again.

May I ask why you have separate virtual drives for all of the parts, and why did you choose VHD which is the most fragile container format?

I have seperate drives for Root because I prefer to have my VM setup as I would on a physical machine, since thats the way I was instructed when I first started playing around with Linux on an old laptop. Furthermore, I do not particularly like LVM for no actual reason except that Im not a big logical volume kind of person. I know it may not be that practical, but it satisfies my OCD. However, the Home partition is seperated because I want to use my SSD for multiple VMs running at the same time and Home does not need the SSDs speed.
Moreover, I chose VHD for the simplicity of being able to mount in my Windows Disk Manager without another third party tool although with ext4 I still need something like Paragon ExtFS. I have been considering changing my system format to VDI and keeping Home as VHD for the above mentioned reasons, but was concerned about compatibiliy as I have not got around to reading about that subject. Future data loss is not life threatening, just an inconvenience, since I do backups regularly.

You really should consider abandoning VHD entirely. You won't appreciate it's convenience quite as much when you find that an entire disk's worth of contents have been lost due to a minor crash.

mpack wrote:You really should consider abandoning VHD entirely. You won't appreciate it's convenience quite as much when you find that an entire disk's worth of contents have been lost due to a minor crash.

I will give VDI a go, but Im assuming this recommendation wont solve my problem or will it? Even if it might fix it I will try it as soon as I get home.

micnip wrote:I have seperate drives for Root because I prefer to have my VM setup as I would on a physical machine, since thats the way I was instructed when I first started playing around with Linux on an old laptop. Furthermore, I do not particularly like LVM for no actual reason except that Im not a big logical volume kind of person. I know it may not be that practical, but it satisfies my OCD. However, the Home partition is seperated because I want to use my SSD for multiple VMs running at the same time and Home does not need the SSDs speed.
Moreover, I chose VHD for the simplicity of being able to mount in my Windows Disk Manager without another third party tool although with ext4 I still need something like Paragon ExtFS. I have been considering changing my system format to VDI and keeping Home as VHD for the above mentioned reasons, but was concerned about compatibiliy as I have not got around to reading about that subject. Future data loss is not life threatening, just an inconvenience, since I do backups regularly.

Really? Well if you want the best of both worlds you should partition the main drive and include the various folders that way. That is what is done on metal. No one uses 5 separate hard drives to run an OS. This in and of itself could cause a timing issue that might actually be your problem.

Oh and using the same home folder on all VMs is risky at best. All of the guests would need to be identical.