Quantum| smartcp Performance Testing (DRAFT) |
This article shows how you can use the smartcp command to gauge the benefits of sparse reads. In a sparse read, data is not read while being written.
This article consists of the following sections:
The following options are taken from the smartcp --help as a reference for the following three examples, Sparse writes on, Sparse writes off, and Doing a full Read/Write. The output of the --help command have been truncated to provide clarity.
Output from smartcp --help comamnd:
Usage: smartcp [OPTION] source destination
or: smartcp [OPTION] source [more source] directory
........ -s <when>, --sparse=<when>
Specify sparse output support.
Valid values for <when> are 'always' and 'never'. Default is 'always'.
........ -v, --verbose
Dump internal information for diagnostic purposes.
........ -g, --debug
Dump more detailed internal information for diagnostic purposes.
This option can be on only when verbose option is also on.
......... -T <format>, --stats-output=<format>
Statistics output format.
Valid values for <format> are 'json' and 'none'. Default is 'none'.
-S <use>, --use-smartread=<use>
Utilize SmartRead if <use> is 'yes'.
Valid values for <use> are 'yes' and 'no'. Default is 'yes'
NEEDS FORMATED LIKE THE OTHERS -JM
Source and Destination Files (with the exception of read or write only mode):
1) <source filename> <desitination filename>
The destination file may or may not exist. If one exist, it will be
overwritten.
2) <source filename> [more source filenames] <desitination directory>
One or multiple source filenames are specified along with a
destination directory. In this case, the directory must exist.
Headers look good. The 'long' verions of the coomand --sparse=<when> illustrates this option better, although -s <when>, the short hand does the same thing. -JM
Here, we we skip read/writes, by using the -s always parameter (which is the default).
The Command:
time smartcp -vg --sparse=always -T json /export/LinuxLab/Fedora/Fedora-flat.vmdk /storage/dxi\ 7500/
The Output:
--------------------------
Options: smart read : on
sparse output: yes
md5 checksum : no
buffer size : 131072
bypass vmp : no
zero scanning: yes
Copying: /export/LinuxLab/Fedora/Fedora-flat.vmdk
To: /storage/dxi 7500/Fedora-flat.vmdk
---- time on open files: 21501 ms
---- 131072 bytes processed, zeros: 0, elapsed time: 22, time on scan: 0 ms, time on read: 3 ms, time on write: 0 ms
{ "r": "data", "v": 1, "t": "22", "total": "8589934592", "copied": "131072", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "23", "total": "8589934592", "copied": "9226240", "write_skipped": "10959872", "read_skipped": "5848064" }
{ "r": "data", "v": 1, "t": "24", "total": "8589934592", "copied": "30036994", "write_skipped": "109424638", "read_skipped": "99713024" }
{ "r": "data", "v": 1, "t": "25", "total": "8589934592", "copied": "36916230", "write_skipped": "247379962", "read_skipped": "225341440" }
{ "r": "data", "v": 1, "t": "26", "total": "8589934592", "copied": "56830986", "write_skipped": "481088502", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "27", "total": "8589934592", "copied": "92089354", "write_skipped": "481088502", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "28", "total": "8589934592", "copied": "122760202", "write_skipped": "481088502", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "29", "total": "8589934592", "copied": "141110282", "write_skipped": "481088502", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "30", "total": "8589934592", "copied": "158805002", "write_skipped": "481088502", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "31", "total": "8589934592", "copied": "175451146", "write_skipped": "486724598", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "32", "total": "8589934592", "copied": "199175178", "write_skipped": "490656758", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "33", "total": "8589934592", "copied": "223423498", "write_skipped": "492884982", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "34", "total": "8589934592", "copied": "248065034", "write_skipped": "493802486", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "35", "total": "8589934592", "copied": "267987978", "write_skipped": "506909686", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "36", "total": "8589934592", "copied": "267987980", "write_skipped": "545051636", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "37", "total": "8589934592", "copied": "267987982", "write_skipped": "587518962", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "38", "total": "8589934592", "copied": "267987986", "write_skipped": "631952366", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "39", "total": "8589934592", "copied": "267987988", "write_skipped": "667866092", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "40", "total": "8589934592", "copied": "267987990", "write_skipped": "702731242", "read_skipped": "454081536" }
---- 985792512 bytes processed, zeros: 263722986, elapsed time: 40, time on scan: 199 ms, time on read: 17707 ms, time on write: 300 ms
###Truncated for simplicity and length####
---- 7845187584 bytes processed, zeros: 2003642226, elapsed time: 234, time on scan: 1307 ms, time on read: 210456 ms, time on write: 4896 ms
{ "r": "data", "v": 1, "t": "235", "total": "8589934592", "copied": "4161424526", "write_skipped": "3698180978", "read_skipped": "1694538752" }
{ "r": "data", "v": 1, "t": "236", "total": "8589934592", "copied": "4181068944", "write_skipped": "3733377904", "read_skipped": "1729735680" }
{ "r": "data", "v": 1, "t": "236", "total": "8589934592", "copied": "4193177234", "write_skipped": "4396757358", "read_skipped": "2391018496" }
---- time on copy contents: 214571 ms
---- time on close files: 726 ms
Stats: file size : 8589934592
read skipped : 2391018496
write skipped: 4396757358
copied bytes : 4193177234
total bytes : 8589934592
scanned zeros: 2005738862
elapsed time : 237 s
time on scan : 1308 ms
time on read : 212812 ms
time on write: 4962 ms
enqueue r q : 214070 ms
dequeue r q : 21573 ms
enqueue w q : 232 ms
dequeue w q : 230948 ms
------------------
real 3m56.807s
user 0m1.836s
sys 0m9.045s
Here, we use the -s never parameter. We don't skip writes, but reads are still skipped.
The Command:
bash-4.1# time smartcp -vg --sparse=never -T json /export/LinuxLab/Fedora/Fedora-flat.vmdk /storage/dxi\ 7500/
The Output:
---------------------------------------------
Options: smart read : on
sparse output: no
md5 checksum : no
buffer size : 131072
bypass vmp : no
zero scanning: yes
Copying: /export/LinuxLab/Fedora/Fedora-flat.vmdk
To: /storage/dxi 7500/Fedora-flat.vmdk
---- time on open files: 118 ms
---- 131072 bytes processed, zeros: 0, elapsed time: 0, time on scan: 0 ms, time on read: 12 ms, time on write: 1 ms
{ "r": "data", "v": 1, "t": "0", "total": "8589934592", "copied": "131072", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "1", "total": "8589934592", "copied": "16253952", "write_skipped": "0", "read_skipped": "4585472" }
{ "r": "data", "v": 1, "t": "2", "total": "8589934592", "copied": "135267328", "write_skipped": "0", "read_skipped": "99713024" }
{ "r": "data", "v": 1, "t": "3", "total": "8589934592", "copied": "210764800", "write_skipped": "0", "read_skipped": "162627584" }
{ "r": "data", "v": 1, "t": "4", "total": "8589934592", "copied": "282067968", "write_skipped": "0", "read_skipped": "224996352" }
{ "r": "data", "v": 1, "t": "5", "total": "8589934592", "copied": "286917632", "write_skipped": "0", "read_skipped": "225995776" }
{ "r": "data", "v": 1, "t": "6", "total": "8589934592", "copied": "525336576", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "7", "total": "8589934592", "copied": "531365888", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "8", "total": "8589934592", "copied": "547225600", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "9", "total": "8589934592", "copied": "568328192", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "10", "total": "8589934592", "copied": "593625088", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "11", "total": "8589934592", "copied": "616693760", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "12", "total": "8589934592", "copied": "646578176", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "13", "total": "8589934592", "copied": "659685376", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "14", "total": "8589934592", "copied": "680001536", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "15", "total": "8589934592", "copied": "709099520", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "16", "total": "8589934592", "copied": "741212160", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "17", "total": "8589934592", "copied": "776470528", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "18", "total": "8589934592", "copied": "803471360", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "19", "total": "8589934592", "copied": "838991872", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "20", "total": "8589934592", "copied": "883556352", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "21", "total": "8589934592", "copied": "916848640", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "22", "total": "8589934592", "copied": "957218816", "write_skipped": "0", "read_skipped": "454081536" }
{ "r": "data", "v": 1, "t": "23", "total": "8589934592", "copied": "980287488", "write_skipped": "0", "read_skipped": "454081536" }
---- 985792512 bytes processed, zeros: -454081536, elapsed time: 23, time on scan: 0 ms, time on read: 21392 ms, time on write: 4116 ms
###Truncated for simplicity and length####
---- 7845187584 bytes processed, zeros: -1694538752, elapsed time: 236, time on scan: 0 ms, time on read: 230786 ms, time on write: 17411 ms
{ "r": "data", "v": 1, "t": "237", "total": "8589934592", "copied": "7855804416", "write_skipped": "0", "read_skipped": "1694538752" }
{ "r": "data", "v": 1, "t": "238", "total": "8589934592", "copied": "7913398272", "write_skipped": "0", "read_skipped": "1729735680" }
{ "r": "data", "v": 1, "t": "245", "total": "8589934592", "copied": "8585990144", "write_skipped": "0", "read_skipped": "2390658048" }
{ "r": "data", "v": 1, "t": "245", "total": "8589934592", "copied": "8589934592", "write_skipped": "0", "read_skipped": "2391018496" }
---- time on copy contents: 245103 ms
---- time on close files: 1268 ms
Stats: file size : 8589934592
read skipped : 2391018496
write skipped: 0
copied bytes : 8589934592
total bytes : 8589934592
scanned zeros: -2391018496
elapsed time : 246 s
time on scan : 0 ms
time on read : 233609 ms
time on write: 24114 ms
enqueue r q : 238228 ms
dequeue r q : 198 ms
enqueue w q : 5246 ms
dequeue w q : 220784 ms
------------------
real 4m6.531s
user 0m0.567s
sys 0m15.354s
As shown in the highlighted real lines in the output of the two commands above, we saved 10 seconds by skipping the writes in this test. Let's see what happens when we disable the read skipping as well.
Same deal here with long hand for smread -JM
Here, we'll do a full read/write with smartcp.
The Command:
time smartcp -vg -s never --use-smartread=no -T json /export/LinuxLab/Fedora/Fedora-flat.vmdk /storage/dxi\ 7500/
The Output:
-----------------------------------------------
Options: smart read : off
sparse output: no
md5 checksum : no
buffer size : 131072
bypass vmp : no
zero scanning: yes
Copying: /export/LinuxLab/Fedora/Fedora-flat.vmdk
To: /storage/dxi 7500/Fedora-flat.vmdk
---- time on open files: 50 ms
---- 131072 bytes processed, zeros: 0, elapsed time: 0, time on scan: 0 ms, time on read: 9 ms, time on write: 0 ms
{ "r": "data", "v": 1, "t": "0", "total": "8589934592", "copied": "131072", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "1", "total": "8589934592", "copied": "33947648", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "2", "total": "8589934592", "copied": "74317824", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "3", "total": "8589934592", "copied": "117571584", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "4", "total": "8589934592", "copied": "141164544", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "5", "total": "8589934592", "copied": "164233216", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "6", "total": "8589934592", "copied": "199098368", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "7", "total": "8589934592", "copied": "228327424", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "8", "total": "8589934592", "copied": "252968960", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "9", "total": "8589934592", "copied": "283377664", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "10", "total": "8589934592", "copied": "310509568", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "11", "total": "8589934592", "copied": "349569024", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "12", "total": "8589934592", "copied": "374341632", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "13", "total": "8589934592", "copied": "403963904", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "14", "total": "8589934592", "copied": "435814400", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "15", "total": "8589934592", "copied": "474087424", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "16", "total": "8589934592", "copied": "509739008", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "17", "total": "8589934592", "copied": "530317312", "write_skipped": "0", "read_skipped": "0" }
---- 537001984 bytes processed, zeros: 0, elapsed time: 17, time on scan: 0 ms, time on read: 17133 ms, time on write: 564 ms
###Truncated for simplicity and length####
---- 8053194752 bytes processed, zeros: 0, elapsed time: 301, time on scan: 0 ms, time on read: 300340 ms, time on write: 9093 ms
{ "r": "data", "v": 1, "t": "302", "total": "8589934592", "copied": "8080982016", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "303", "total": "8589934592", "copied": "8101953536", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "304", "total": "8589934592", "copied": "8130002944", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "305", "total": "8589934592", "copied": "8154906624", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "306", "total": "8589934592", "copied": "8179154944", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "307", "total": "8589934592", "copied": "8211005440", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "308", "total": "8589934592", "copied": "8233287680", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "309", "total": "8589934592", "copied": "8252293120", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "310", "total": "8589934592", "copied": "8283226112", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "311", "total": "8589934592", "copied": "8316256256", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "312", "total": "8589934592", "copied": "8350334976", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "313", "total": "8589934592", "copied": "8374321152", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "314", "total": "8589934592", "copied": "8403156992", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "315", "total": "8589934592", "copied": "8433696768", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "316", "total": "8589934592", "copied": "8466595840", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "317", "total": "8589934592", "copied": "8498577408", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "318", "total": "8589934592", "copied": "8517320704", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "319", "total": "8589934592", "copied": "8542486528", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "320", "total": "8589934592", "copied": "8572502016", "write_skipped": "0", "read_skipped": "0" }
{ "r": "data", "v": 1, "t": "320", "total": "8589934592", "copied": "8589934592", "write_skipped": "0", "read_skipped": "0" }
---- time on copy contents: 320669 ms
---- time on close files: 959 ms
Stats: file size : 8589934592
read skipped : 0
write skipped: 0
copied bytes : 8589934592
total bytes : 8589934592
scanned zeros: 0
elapsed time : 321 s
time on scan : 0 ms
time on read : 320017 ms
time on write: 9667 ms
enqueue r q : 320452 ms
dequeue r q : 113 ms
enqueue w q : 423 ms
dequeue w q : 310804 ms
------------------
real 5m21.688s
user 0m0.749s
sys 0m15.688s
As shown by the highlighted real lines in the two output listings above, we see a difference of 1:25 (1 minute, 25 seconds), from 3m56.807s (in the Turning Sparse Output ON section) to 5m21.688s here. That's over a 25% performance difference.
On a small scale of this meager VM, it's not much. Spread across 1TB we could save 250GB, which at 100MB/sec, could mean a 40min difference in a backup window. Concrete example given. DF command nto needed, no idea why i included that -JM
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