External encapsulation of a volume into a LUN to allow booting and installation on a complex volume
A system for external encapsulation of a volume into a logical unit (LUN) to allow booting and installation on a complex volume may include a host, one or more physical storage devices, and an off-host virtualizer. The off-host virtualizer (i.e., a device external to the host, capable of providing block virtualization functionality) may be configured to aggregate storage within the one or more physical storage devices into a logical volume and to generate metadata to emulate the logical volume as a bootable target device. The off-host virtualizer may make the metadata accessible to the host, allowing the host to boot off a file system resident in the logical volume.
1 . A system comprising:
a host;
one or more physical storage devices;
an off-host virtualizer;
wherein the off-host virtualizer is configured to:
aggregate storage within the one or more physical storage devices into a logical volume; and
generate metadata to emulate the logical volume as a bootable target device;
make the metadata accessible to the host; and
wherein the host is configured to use the metadata to boot off a file system residing in the logical volume.
2 . The system as recited in claim 1 , wherein the logical volume is a snapshot volume.
3 . The system as recited in claim 1 , wherein the logical volume is a replicated volume.
4 . The system as recited in claim 1 , wherein the logical volume is a striped volume.
5 . The system as recited in claim 1 , wherein the one or more physical storage devices include a first and a second physical storage device, and wherein the logical volume spans the first and the second physical storage devices.
6 . The system as recited in claim 1 , wherein the logical volume is a RAID volume.
7 . The system as recited in claim 1 , wherein the logical volume maps to a boot partition of a designated operating system.
8 . The system as recited in claim 7 , wherein the designated operating system is configured to access a plurality of additional boot-related partitions during a boot operation, and wherein the off-host virtualizer is further configured to:
generate additional metadata to emulate the logical volume as the plurality of additional boot-related partitions; and
make the additional metadata accessible to the host.
9 . The system as recited in claim 1 , wherein, subsequent to an initial phase of a boot process, the host is configured to access the logical volume directly without performing I/O through the off-host virtualizer.
10 . The system as recited in claim 9 , wherein the host is configured to use a first network type for the initial phase of the boot process, and wherein the host is configured to access the logical volume directly using a second network type.
11 . The system as recited in claim 1 , wherein a physical storage device of the one or more physical storage devices includes a fiber channel logical unit (LUN).
12 . The system as recited in claim 1 , wherein a physical storage device of the one or more physical storage devices includes an iSCSI LUN.
13 . The system as recited in claim 1 , further comprising a storage server, wherein the storage server is configured to provide access to a physical storage device of the one or more physical storage devices.
14 . The system as recited in claim 1 , wherein a physical storage device of the one or more physical storage devices is accessed using a target-mode host bus adapter of the off-host virtualizer.
15 . The system as recited in claim 1 , wherein the off-host virtualizer is further configured to:
present the logical volume to the host as an installable partition;
and wherein the host is further configured to:
boot installation software for the operating system from removable media; and
install the at least a portion of the operating system on the installable partition.
16 . A method comprising:
aggregating storage within one or more physical storage devices into a logical volume;
generating metadata to emulate the logical volume as a bootable target device;
making the metadata accessible to a host; and
the host using the metadata to boot off a file system resident in the logical volume.
17 . The method as recited in claim 16 , wherein the logical volume is a snapshot volume.
18 . The method as recited in claim 16 , wherein the logical volume is a replicated volume.
19 . The method as recited in claim 16 , wherein a storage device of the one or more physical storage devices includes a fibre channel logical unit (LUN).
20 . The method as recited in claim 16 , wherein a storage device of the one or more physical storage devices includes an iSCSI (Internet SCSI) LUN.
21 . The method as recited in claim 16 , further comprising:
the host accessing the logical volume subsequent to the boot operation without performing I/O through the off-host virtualizer.
22 . A computer accessible medium comprising program instructions, wherein the instructions are executable to:
aggregate storage within one or more physical storage devices into a logical volume;
generate metadata to emulate the logical volume as a bootable target device;
make the metadata accessible to a host; and
use the metadata to boot the host off a file system resident in the logical volume.
23 . The computer accessible medium as recited in claim 22 , wherein the logical volume is a snapshot volume.
24 . The computer accessible medium as recited in claim 22 , wherein the logical volume is a replicated volume.
25 . The computer accessible medium as recited in claim 22 , wherein a storage device of the one or more physical storage devices includes a fibre channel logical unit (LUN).
26 . The computer accessible medium as recited in claim 22 , wherein a storage device of the one or more physical storage devices includes an iSCSI (Internet SCSI) LUN.
27 . The computer accessible medium as recited in claim 22 , wherein the instructions are further executable to:
access the logical volume from the host subsequent to the boot operation without performing I/O through the off-host virtualizer.