[SOLVED] Comp 3700: project 2 audisktool – a tool for monitoring disk devices

1. Building your Linux disk monitoring tool – auDiskTool
In this project, you have a Linux tool called – auDiskTool – to monitor disk performance (i.e.,
I/O transfer rates) in a Linux system. Your auDiskTool can output a file containing a list of
reports (attached at the end) that help system administrators in configuring the Linux system
to achieve good disk I/O performance.
The monitoring reports created and maintained by your auDiskTool offers statistical
information on I/O transfer rates. Our long-term goal is building a tool to monitor both
processor and disk performance of Linux systems. However, the short-term goal to be achieved
in this project is to generate a state diagram. After you complete this project, you may extend
your auDiskTool to monitor processor performance in addition to disk performance.
2. Requirements
2.1. Statistical Information
Each report item recorded in an output file contains statistics on a per disk or partition basis.
auDiskTool allows users to choose a particular disk or partition to monitor. If no disk nor
partition is chosen by the users, then auDiskTool monitors all disks used by the Linux system.
Each report item may show the following information:
Device: This column provides the disk or partition name (e.g., sda). If your Linux machine has
new kernels, the device name listed in the /dev directory is displayed. If your Linux kernel is 2.4,
the format of the names is devm-n, where m is the major number of the device, and n is a
distinctive number. If your Linux kernel is 2.2 (this is an uncommon case), the name will be
displayed as hdiskn.
Blk_read:
This column reports the total number of reads.
Blk_read/s:
This column indicates the number of reads from the disk per second.
KB_read/s:
This column indicates the amount of data blocks read from the disk per second (i.e., measured
in Kilobytes per second). Note: we assume the size of sector is 1 KB.
Blk_wrtn:
This column reports the total number of blocks written.
KB_wrtn/s:
This column indicates the number of data blocks written to the disk per second. (i.e., measured
in Kilobytes per second.)
Blk_wrtn/s:
This column indicates the number of data blocks written to the disk per second.
2.2. Configure Time Interval and Count
Your auDiskTool can set an interval parameter, which specifies the amount of time measured in
seconds between two consecutive disk reports. Each disk report contains statistics collected
during the interval since the previous report is recorded. Your auDiskTool also can decide the
number of reports to be collected in an output file. If the interval parameter and the count
parameter are not specified, auDiskTool may use default values. For example, the default value
of the interval parameters is 1 second; the default value of the count parameter is 10.
2.3. Specify the File Name of an Output Report
Your auDiskTool should allow users to specify the file name of an output report. The file name
may be fully specified with a path. If no path is provided, then the working directory will be the
current directory where the new report file is created. If the output file exists, then new report
items will be appended at the end of the existing file.
Note 1: If users specify a file name that does exist, auDiskTool must inform users that an output
report file with the same name exists and reported items will be added to the existing file.
Note 2: If the report file name is not specified, then “report.adt” will be used as a default
output file name.
2.4. Specify what statistical data to be reported
In section 3.1, we list 7 statistical data items. Your tool should allow users to decide what data
items to be included in a report. A configuration file (see Section 3.5 blow) stores default
values for these decisions.
2.5. A Configuration File – audisktool.conf
All the default parameters (e.g., time interval, count, output file name) are stored in a
configuration file. This configuration file is loaded into main memory when auDiskTool starts its
execution. The configuration file name is “audisktool.conf”. The format of the configuration file
is:
Interval, count, print_blk_read, print_blk_read/s,
print_kb_read/s, print_blk_write, print_blk_write/s,
print_kb_write/s
The values of print_blk_read, print_blk_read/s, print_kb_read/s, print_blk_write,
print_blk_write/s, print_kb_write/s can be either ‘1’ or ’0’. ‘1’ means that the value will be
reported; ‘0’ means the value is ignored in the report.
For example, suppose we have the following configuration file:
5 10 1 1 1 0 0 0
The above file indicates that Interval is 5 seconds, count is 10, report values of blk_read,
blk_read/s, kb_read/s and do not include the values of blk_write, blk_write/s, kb_write/s in the
report.
You do not need to submit this configuration file via Canvas; the TA will use the configuration
file with the following parameters to test your implementation:
1 10 1 1 1 1 1 1
2.6. Display the report
Users are allowed to open the report and display monitoring records inside audisktool. If the
report file does not exist or cannot be opened, audisktool must show a warning message.
2.7. System Quit
This should safely terminate the audiskTool. If any parameter (e.g., time interval and count) is
updated, the system parameters must be saved back to the configuration file called
“audisktool.conf”.
3. Retrieve Disk Statistics
The Linux (version 2.4.20 and above) operating system offers extensive disk statistics to
measure disk activities. You can use the following command to check the version of your Linux:
$uname -r
Linux Version 2.6 and above:
The disk statistical information can be found in
/proc/diskstats
You can use the following command to display this file:
$cat /proc/diskstats
Example 1: Below is an example to show the format of the above file:
3 0 sda 446216 784926 9550688 4382310 424847 312726 5922052 19310380
0 3376340 23705160
3 1 sda1 2 0 4 24 0 0 0 0 0 24 24
You also can use the following command to display the information related to disks in the
/proc/diskstats file.
$grep ‘sda’ /proc/diskstats
Note that grep is a utility program for searching plain-text data sets for lines matching a
regular expression (e.g., ‘sda’ in our case).
4. Format of “/proc/diskstats”
In example 1 shown on page 4, you can find each row has 14 items. The first three items are the
major and minor device numbers, and device name. For example, given the following row:
3 1 sda1 2 0 4 24 0 0 0 0 0 24 24
The major device number is 3, and minor device number is 1, and device name is sda1.
The 11 fields listed after the device name are statistics data of the device whose major/minor
device numbers as well as name are shown in the first three fields. All these 11 fields except
field 9 are cumulative since boot. Note that field 9 goes to zero as I/Os complete; all others
only increase. These fields are unsigned long numbers.
The 11 fields are explained below:
Field 1: # of reads completed. This is the total number of reads completed successfully.
Field 2/6: # of reads/writes merged. Reads and writes which are adjacent to each other may be
merged for efficiency. Thus two 4K reads may become one 8K read before it is ultimately
handed to the disk, and so it will be counted (and queued) as only one I/O. This field lets you
know how often this was done.
Field 3: # of sectors read. This is the total number of sectors read successfully.
Field 4: # of milliseconds spent reading. This is the total number of milliseconds spent by all
reads (as measured from make_request() to end_that_request_last()).
Field 5: # of writes completed. This is the total number of writes completed successfully.
Field 7: # of sectors written. This is the total number of sectors written successfully.
Field 8: # of milliseconds spent writing. This is the total number of milliseconds spent by all
writes (as measured from make_request() to end_that_request_last()).
Field 9: # of I/Os currently in progress. The only field that should go to zero. Incremented as
requests are given to appropriate struct request_queue and decremented as they finish.
Field 10: # of milliseconds spent doing I/Os. This field increases so long as field 9 is nonzero.
Field 11: weighted # of milliseconds spent doing I/Os. This field is incremented at each I/O
start, I/O completion, I/O merge, or read of these stats by the number of I/Os in progress (field
9) times the number of milliseconds spent doing I/O since the last update of this field. This can
provide an easy measure of both I/O completion time and the backlog that may be
accumulating.
5. Rubrics:
1. Please list class names. (18 points)
2. Use argoUML to create a state chart diagram. (10 points)
3. For each class, please add proper info – at least one attribute and operation. If no ops,
please indicate N/A– for software engineers to define them. (16 points)
4. Please indicate the relationship among classes with proper types of lines. (20 points)
5. Please indicate the conditions for transitions. (16 points)
6. Please specify the multiplicity. (15 points)
7. Submit your solution on Canvas with the format: project2_firstname.zargo. (5 points)
6. No Late Submission
• Late submissions will not be accepted and will result in a ZERO without valid excuses,
in which case you should talk to Dr. Li to explain your situation.
• GTA/Instructor will NOT accept any late submission caused by Internet latency.
7. Rebuttal period
• You will be given a period of two business days to read and respond to the comments
and grades of your homework or project assignment. The TA may use this opportunity
to address any concern and question you have. The TA also may ask for additional
information from you regarding your homework or project.
Sample Usage
1. Help
$./audisktool_aak0010 <- aak0010 is a TA username
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>help
run – run the monitoring tool.
set interval [value] – set sampling period to [value] set
count [value] – set the number of records to [value] set
report [name] – set report file name to [name]
set blk_read [0|1] – set print_blk_read to 0 or 1 set
blk_read/s [0|1] – set print_blk_read/s to 0 or 1 set
kb_read/s [0|1] – set print_kb_read/s to 0 or 1 set
blk_write [0|1] – set print_blk_write to 0 or 1 set
blk_write/s [0|1] – set print_blk_write/s to 0 or 1 set
kb_write [0|1] – set print_kb_write to 0 or 1 print
conf – display all the parameters
print report – open and display the report file
save – the configuration file audisktool.conf is updated
display – exit – exit the tool.
>
2. Run the tool
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>run
Monitoring time = 5 Seconds, Number of records = 10, print_blk_read =
1, print_blk_read/s = 1, print_kb_read/s = 1,
print_blk_write = 0, print_blk_write/s = 0, print_kb_write/s = 0, report
file name = ‘report.adt’
Please wait …
A file “report.adt” is updated.
>
3. Change report file name
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>set report aak0010.adt
The report file name is changed from ‘report.adt’ to ‘aak0010.adt’. You
can now type ‘run’ to generate new records to be saved in ‘aak0010.adt’.
Note: ‘report.adt’ will not be deleted by audisktool.
>
4. Display records in the report file
4.1 no record is found
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>print report
No record found in ‘report.adt’
>
4.2 Records are found
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>print report
2 records found in ‘report.adt’
blk_read blk_read/s kb_read/s blk_write blk_write/s kb_write/s
10 1.13 2.26 N/A N/A N/A
55
>
5.4 10.8 N/A N/A N/A
5. Change count and interval
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>set count 15
The number of records generated in each run has been changed to 15.
>set interval 3
The sampling interval has been changed to 3 seconds.
>
6. Change print_blk_read and other similar parameters
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>set blk_read 0
Print_blk_read has been changed to 0.
>set blk_write 0
Print_blk_write was 0; the parameter remains unchanged to 0.
>
7. Display all the parameters.
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>print conf
Monitoring time = 5 Seconds, Number of records = 10, print_blk_read =
1, print_blk_read/s = 1, print_kb_read/s = 1,
print_blk_write = 0, print_blk_write/s = 0, print_kb_write/s = 0, report
file name = ‘report.adt’
>
8. Save the configuration file
8.1 no need to save
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>save
audisktool.conf has not been updated. There is no need to save the file.
8.2 change can save the configuration file
$./audisktool_aak0010
auDiskTool, version 1.0.0. Type ‘help’ to find more about commands.
>set blk_read 0
Print_blk_read has been changed to 0.
>save
file audisktool.conf has been updated.
>