Simulate Disk Faults

This document describes how to use Chaosd to simulate disk faults. This feature helps you simulate disk read/write load (via dd) or disk fill (via dd or fallocate).

Before creating an experiment, you can run the following command to check the types of disk faults that are supported by Chaosd:

chaosd attack disk -h

Currently, Chaosd supports creating disk read load experiments, disk write load experiments, and disk fill experiments.

To create experiments using the service mode, you need to run Chaosd in the service mode and then send a POST HTTP request to the /api/attack/disk path of the Chaosd service:

chaosd server --port 31767

curl -X POST 172.16.112.130:31767/api/attack/disk -H "Content-Type:application/json" -d '{fault-configuration}'

For the fault-configuration part in the above command, you need to configure it according to the fault types. For the corresponding parameters and examples, refer to the parameters of each fault type in the following sections.

info

When running an experiment, remember to record the UID of the experiment. When you want to end the experiment corresponding to the UID, you need to send a DELETE HTTP request to the /api/attack/{uid} path of the Chaosd service.

Simulate disk read load

Parameters for simulating disk read load

Configuration item	Abbreviation	Service mode field	Description	Type	Value
action	—	action	Actions of the experiment	string	Set to "read-payload"
path	p	path	Specifies the file path to read the data. If this parameter is not specified, or the parameter value is set to an empty string, Chaosd reads from the virtual disk files mounted in the "/" directory. Depending on the permissions to read the files, you might be required to run this program using certain permissions.	string	Default: ""
process-num	n	payload-process-num	Specifies the number of concurrently running dd programs to be used.	uint8	Default: 1; range: 1 to 255
size	s	size	Specifies the volume of data to be read. It is the total size of data that dd reads.	string	Default: ""; required; legal form: the combination of an integer and a unit. For example, 1M, 512kB. Supported units are c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, GB=1000*1000*1000, G=1024*1024*1024*1024 BYTE and so on.

Simulate disk read load using the command-line mode

Simulating disk read load is a one-time operation, so the experiment does not need to be recovered.

Commands for simulating disk read load

chaosd attack disk add-payload read -h

Example for simulating disk read load

chaosd attack disk add-payload read -s 1000G -n 7 -p /dev/zero

Simulate disk read load using the service mode

curl -X POST 172.16.112.130:31767/api/attack/disk -H "Content-Type:application/json" -d '{"action":"read-payload","path":"/dev/zero", "payload-process-num":7,"size":"1000G"}'

Simulate disk write load

Parameters for simulating disk write load

Configuration item	Abbreviation	Service mode field	Description	Type	Value
action	—	action	Actions of the experiment	string	Set to "write-payload"
path	p	path	Specifies the file path to write the data. If this parameter is not specified, or the parameter value is set to an empty string, a temporary file will be created in the program execution directory. Depending on the permissions to write the files, you might be required to run this program using certain permissions.	string	Default: ""
process-num	n	payload-process-num	Specifies the number of concurrently running dd programs to be used.	uint8	Default: 1; range: 1 to 255
size	s	size	Specifies the volume of data to be written. It is the total size of data that dd writes.	string	Default: ""; required; legal form: the combination of an integer and a unit. For example, 1M, 512kB. Supported units are c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, GB=1000*1000*1000, G=1024*1024*1024*1024 BYTE and so on.

Simulate disk write load using the command-line mode

Command for simulating disk write load

chaosd attack disk add-payload write -h

Example for simulating disk write load

chaosd attack disk add-payload write -s 2G -n 8

Simulate disk write load using the service mode

curl -X POST 172.16.112.130:31767/api/attack/disk -H "Content-Type:application/json" -d '{"action":"write-payload","path":"/tmp/test", "payload-process-num":7,"size":"1000G"}'

Simulate disk fill

Parameters for simulating disk fill

Configuration item	Abbreviation	Service mode field	Description	Type	Value
action	—	action	Actions of the experiment	string	Set to "fill"
destroy	d	destroy	If this parameter is set to true, the fill file is immediately deleted after being filled.	bool	Default: false
fallocate	f	fill-by-fallocate	If this parameter is set to true, Linux is used to call fallocate to quickly apply for disk space and size must be greater than 0. If this parameter is set to false, Linux is used to call dd to fill disks at a relatively slow pace.	bool	Default: true
path	p	path	Specifies the file path to write the data. If this parameter is not specified, or the parameter value is set to an empty string, a temporary file will be created in the program execution directory. Depending on the permissions to write the files, you might be required to run this program using certain permissions.	string	Default: ""
percent	c	percent	Specifies the percentage of disk size to be filled.	string	Default: ""; positive integer of the uint type is acceptable; you must set one of size or percent (both items cannot be "" at the same time).
size	s	size	Specifies the volume of data to be written.	string	Default: ""; legal form: the combination of an integer and a unit. For example, 1M, 512kB. Supported units are c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, GB=1000*1000*1000, G=1024*1024*1024*1024 BYTE and so on. You must set one of size or percent (both items cannot be "" at the same time).

Simulate disk fill using the command-line mode

Command for simulating disk fill

chaosd attack disk fill -h

Example for simulating disk fill

chaosd attack disk fill -c 50 -d

Simulate disk fill using the service mode

curl -X POST 172.16.112.130:31767/api/attack/disk -H "Content-Type:application/json" -d '{"action":"fill","path":"/tmp/test", "fill-by-fallocate":true,"percent":"50"}'