Drives
What are Drive States in Virtual Machines?
Drive states indicate how a drive is attached to a VM, edited, shared, or deleted.
Initializing State
Drives in initializing state cannot be used for any operations because the system is currently performing an action on the drive, making it not ready yet.
Ready State
The ready state means the drive is fully available for use. It indicates that the drive is ready to be attached and mounted.
Read-only State
Each Virtual Machine is typically attached to a drive as read-only for all users except the drive owner, which provides default access to the drive.
Drives can be mounted read-only in other VMs but can never be used as read-write.
Drives can be shared as read-only with other users. When you Add Users to a Virtual Machine, the drive attached to the VM is automatically shared as read-only.
Read-write State
Read-write access is more sensitive and should only be granted to drive owners.
A drive mounted in read-write state is exclusive in the entire system and cannot be used by anything else besides the VM that is using it. Once the VM releases the read-write drive, it can be used in other VMs.
As a best practice, there should be two drive owners per drive. If one owner is unavailable or leaves the organization, the other can manage the drive as needed.
Read-write access allows drive owner to Unshare the drive from everyone else, making the owner the sole user with access.
A user who shares a drive as read-write can further share it as read-write with other users.
You cannot have a drive combination between read-write and read-only.
Create Drives
| Read-only | Read-write |
|---|---|
| Users can add files. | User can take ownership of the drive files. |
| Users can view the files. | User can edit the files. |
Edit Drives
| Read-only | Read-write |
|---|---|
| Users cannot make any edits to the drive. | User can edit the drive. |
| Users can bulk email other drive users. | User can rename the drive. |
| Users cannot access project tags in the drive. | User can change the project tag in the drive. |
| Users cannot classify projects in the drive. | User can classify and declassify projects in the drive. |
Share Drives
| Read-only | Read-write |
|---|---|
| Users can share the drive as read-only. | User can share the drive in both as read-only and read-write. |
| Users cannot unshare the drive. | User can unshare the drive with everyone else. |
| Users cannot edit drive ownership. | User can directly transfer ownership of the drive. |
Follow the instructions in Share a Drive with Other Users for sharing in Ready-write or Give Read-Only Access of a Drive to a User for sharing in Read-Only.
What is the Drive State when Deleting a Drive?
tiCrypt uses the attached state in the deletion drive prompt because the action comes solely from the backend (external view) which means the backend only sees the drive as attached. The backend does not know if the drive was mounted or unmounted. A 60-second delay is added before performing the deletion action because it is a very disruptive operation, and recovery is very difficult.
What are Drive Types in Virtual Machines?
Analogy
Imagine there are always two points of view when it comes to drive types:
The External point of view: what the backend can see. The external view (or hardware view) describes physically removing and reinserting a drive from a running local machine.
The Internal point of view: what the VM controller can see. The internal view (or software view) describes the action of allowing the local machine to virtually recognize the drive as registered and functioning correctly.
Mounted & Attached Type
Similar to the analogy above, the backend makes external view point decisions by only attaching or unattaching the drive to the VM. However, for a drive to be in use, it also needs an internal view point. The VM controller makes internal view point decisions by mounting or unmounting the drive within the VM.
Even if you own the drive, if you are not a VM manager you do not know if the drive is mounted or unmounted.
Home Type
The first default read-write drive that allows the VM to start is a home type drive. This drive must be always read-write; otherwise, the VM owner will not be able to perform any actions within the VM.
Mounted & Unattached Type
In some cases, it is possible for a drive to be attached but not mounted. If this occurs, you can use the Repair an Unattached Drive in a Virtual Machine workflow.
Unattached Type
The drive does not show up in the VM Configuration; however, the system is aware that the drive is not attached by the backend.
Unmounted Type
The drive is attached but not mounted. This is a scenario every admin should strictly avoid. When this happens, it means something went wrong and you need to repair it.
Unknown Type
The unknown type means the system could not determine what is happening with the drive. As a result, things cannot be computed correctly. In this scenario, you may need to go beyond the drive functionality and find whether you need to add more computing resources or if the issue is external.
What are the Drive Formats in Virtual Machines?
System admins may select the appropriate formats to help each group meet their research goals. Linux allows you to use a wide variety of formats since it is open-source.
| File System | Windows | Linux |
|---|---|---|
| NTFS | Full support | Read/Write (via ntfs-3g or kernel driver) |
| BTRFS | Not supported | Full support |
| EXT4 | Not supported | Full support |
| XFS | Not supported | Full support |
| ZFS | Not supported | Full support (may require ZFS packages) |
The file system choice depends on the tools you have installed.
How Does the Public-Private Key Mechanism Work when Creating a Drive?
When you create a drive, it is encrypted automatically using your public key and a symmetric key generated by the system. The encrypted data is then sent and stored on the server.
How Does the Public-Private Key Mechanism Work when Sharing a Drive?
When you share a drive with another user, your private key decrypts the symmetric key used to secure the drive. The system then uses the receiver's public key to create a version of the symmetric key, which is sent to the server.
This cryptographic process ensures that only users who created or were added to the drive can access it. Even admins cannot grant themselves access or take over drives.
If the drive is unmounted from your VM, read-write allows shared users to write to the drive but not share it with others.
What are the Best Practices for Transferring Drive Ownership?
Before transferring drive ownership, you must explicitly share the drive with the new owner as read-write. Then follow the instructions from the Transfer Ownership of the Drive to a Different User.
When are the Project Changes in Drives Audited?
All project changes in drives are audited automatically and permanently at all times.
What is the Difference Between the Home Drive Usage and the Memory Usage in the Virtual Machine?
Memory usage allows for computation power while home drive usage allows for drive space.
Imagine a library with many books, where you need a desk to collect the right books, open them, and read them.
The home drive usage (persistent storage) is your data library, while the memory usage (ephemeral storage) is your desk.
While most operations happen in the memory (your desk), where you can access files faster, you must pick up the files from the home drive (your library).
When you leave the session, everything goes away from your desk back to the library.
Role of the Virtual Machine
Your Virtual Machine pairs the computational ability of the home drive with the memory.
It acts as the brain of usage management. As a result, the CPU becomes indispensable.
Operating at maximum memory may cause your VM to crash.
To maintain a balance between home drive usage and memory usage, consult your research group to determine the memory and disk space requirements for their projects and software.
Follow the instructions from the View Drive Basic Information.
What is the Storage Difference Between Hard Drives and Memory Usage in a VM Configuration?
Hard drive: persistent storage.
Memory usage: ephemeral storage.
The difference between memory usage and hard drives is that memory functions as an operation center, while persistent data is stored on hard drives.