This is a memory block device driver for IO errors and crash test, emulating read/write IO error and device crash (or sudden shutdown). This also supports configurable delay for read, write and flush IOs.
- Crash emulation.
- Sudden crash emulation will delete non-persistent data.
- IO error emulation.
- IO will fail in the error states.
- Configurable response time of read/write/flush IO.
- You can reproduce various performance behavior of storage devices.
GPLv2 or 3.
| Branch | Kernel version |
|---|---|
| master | 4.3-(4.7) |
| for-3.14 | 3.14-4.2 |
| for-3.10 | 3.10-3.13 |
> cd crashblk.git/module
> make
> sudo insmod crashblk-mod.ko
Use KERNELDIR, DEBUG make options to customize your build.
See module/Makefile for details.
> cd crashblk.git/tool
> make
> sudo cp -a crashblkc /usr/local/bin/
Use DEBUG make option to customize your build.
To show command list, type as follows:
> crashblkc
Create a device with 1GiB:
> sudo crashblkc create 1G
0
You will get /dev/crashblk0 of 1GiB size.
Internally the module will use 2GiB+ memory
for cache and original data.
Delete a device:
> sudo crashblkc delete /dev/crashblk0
You can create two or more devices.
Make a device in error state:
> sudo crashblkc io-error /dev/crashblk0 MODE
You can specify MODE as r, w, or rw.
| Mode | Description |
|---|---|
r |
read IOs fail |
w |
write IOs fail |
rw |
all IOs fail |
Make a device in crash state:
> sudo crashblkc crash /dev/crashblk0
Not flushed data will be lost.
Recover a device from crash/io-error state:
> sudo crashblkc recover /dev/crashblk0
Of course the lost data will not recovered. Use this for crash test of file systems or so.
Set response times:
> sudo crashblkc set-delay-ms /dev/crashblk0 READ_MIN READ_MAX WRITE_MIN WRITE_MAX FLUSH_MIN FLUSH_MAX
For each kind of IO, read, write, and flush, IO response time will be randomly determined between the specified min and max values. Set both 0 to disable additional delay.
Get response times:
> sudo crashblkc get-delay-ms /dev/crashblk0
(C) 2014 Cybozu Labs, Inc.