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- ======
- dm-ebs
- ======
- This target is similar to the linear target except that it emulates
- a smaller logical block size on a device with a larger logical block
- size. Its main purpose is to provide emulation of 512 byte sectors on
- devices that do not provide this emulation (i.e. 4K native disks).
- Supported emulated logical block sizes 512, 1024, 2048 and 4096.
- Underlying block size can be set to > 4K to test buffering larger units.
- Table parameters
- ----------------
- <dev path> <offset> <emulated sectors> [<underlying sectors>]
- Mandatory parameters:
- <dev path>:
- Full pathname to the underlying block-device,
- or a "major:minor" device-number.
- <offset>:
- Starting sector within the device;
- has to be a multiple of <emulated sectors>.
- <emulated sectors>:
- Number of sectors defining the logical block size to be emulated;
- 1, 2, 4, 8 sectors of 512 bytes supported.
- Optional parameter:
- <underlying sectors>:
- Number of sectors defining the logical block size of <dev path>.
- 2^N supported, e.g. 8 = emulate 8 sectors of 512 bytes = 4KiB.
- If not provided, the logical block size of <dev path> will be used.
- Examples:
- Emulate 1 sector = 512 bytes logical block size on /dev/sda starting at
- offset 1024 sectors with underlying devices block size automatically set:
- ebs /dev/sda 1024 1
- Emulate 2 sector = 1KiB logical block size on /dev/sda starting at
- offset 128 sectors, enforce 2KiB underlying device block size.
- This presumes 2KiB logical blocksize on /dev/sda or less to work:
- ebs /dev/sda 128 2 4
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