On Monday 01 June 2009 18:03:38 Randall R Schulz wrote:
On Monday June 1 2009, Anders Johansson wrote:
On Monday 01 June 2009 17:23:42 Randall R Schulz wrote:
Do you know any block devices these days that aren't disks or flash drives?
Optical devices (CD, DVD, BluRay), iSCSI, FCoE, ATAoE, nbd, loopback devices, ram disks
And how many of them (that are not in fact disks or intermediaries to disks) are suitable for acting as the physical storage for a VMware virtual disk? Certainly not any of the optical types.
Aside from performance, why not? Most of the time a disk doesn't even have to be writable. It is perfectly possible to have almost all your file system running on a DVD (for example), though from a performance perspective perhaps not desirable
The rest are interconnects or mediators to some physical storage. If that storage isn't random access (disk), then it's not suitable as the physical representation of a virtual machine's virtual disk.
The way you write "random access (disk)" makes me think you somehow equate the two, and obviously if you say "anything that is usable as a root device is by definition a disk" then it is obviously a disk. But I don't accept that equality. The point was that any block device can be used, simply because they behave in a sufficiently equivalent way. None of the ones I listed are disks, but they share behaviour with disks, not because they are disks in any way, but because they speak the same communication protocols as disks of various types. What is at the other end of that protocol is supposed to be a black box, as long as it fulfills the semantics of the protocol.
I'm pretty sure DECtape is officially obsolete.
I have seen people export tape devices as nfs shares. Not sure what brand it was, but it seemed to work (but slooooow of course :)
Magnetic tape (of the standard 9-track variety, at least) is not rewritable because the drive does not ensure that a new record precisely aligns with the one being overwritten.
As I said, I don't know what they were using exactly, but it was definitely a tape drive of some kind. Not to be recommended, of course Anders -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org