Data Domain: Understanding System Show Performance Output
Summary: Understanding system show performance view legacy (SSP) in DDOS
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The SSP commands are available in the regular DDOS CLI. It processes the performance log and gives a good overview of many DD system performance metrics for a given period of time at the chosen sampling intervals.
The command syntax is:
system show performance view legacy command (also referred to as SSP) in DDOS systems. SSP processes performance logs and presents key metrics for system performance over a specified time range and interval. This article focuses only on the legacy view output and does not cover the non‑legacy system show performance format.
The SSP commands are available in the regular DDOS CLI. It processes the performance log and gives a good overview of many DD system performance metrics for a given period of time at the chosen sampling intervals.
The command syntax is:
system show performance view legacy [ duration <duration> {hr | min} [interval <interval> {hr | min}] ]- Both the "duration" and the "interval" modifiers are optional.
- If none is provided, stats are printed for the last 24 hours at 10 minute intervals. This is the information printed in the daily
autosupports(ASUPs) under the section. -
If omitted, the system displays the last 24 hours at 10‑minute intervals, matching the data in ASUPs ("
SYSTEM SHOW PERFORMANCE LEGACY VIEW" section). -
The most granularly supported interval is 1 minute.
- If none is provided, stats are printed for the last 24 hours at 10 minute intervals. This is the information printed in the daily
- Both the "duration" and the "interval" modifiers are optional.
When passing these options, the command line would be as follows (the command below returns the same as the command with no options):
system show performance view legacy duration 24 hr interval 10 min- This shows the system performance for the last 24 hours at 10 minute intervals. The most granular interval is set to 1 minute.
The sample command output for any supported DDOS (7.x+) is as below:
-----------Throughput (MB/s)----------- ---------------Protocol----------------- Compression ------Cache Miss-------- -----------Streams----------- -MTree Active- -State- -----Utilization----- --Latency-- --------------------SS LOAD BALANCE(user/repl)--------------------- -----------------SS LOAD BALANCE(gc)--------------------
Repl
Date Time Read Write Repl Network Repl Pre-comp ops/s load data(MB/s) wait(ms/MB) gcomp lcomp thra unus ovhd data meta rd/ wr/ r+/ w+/ in/ out rd/wr 'CDPVMSFIRL' CPU disk in ms stream prefetch rd wr tot prefetch rd wr tot
---------- -------- ----- ----- ----in/out--- ----in/out--- ----- --%-- --in/out--- --in/out--- ----- ----- ---- ---- ---- ---- ---- ----------------------------- -------------- --------- -avg/max---- --max--- --avg/sdev- ----------------------------avg/sdev------------------------------- ----------------------------avg/sdev--------------------
2026/02/03 09:37:00 175.8 444.0 7.45/734.06 0.00/5479.44 698 3936.09% 38.35/167.96 0.87/ 0.37 11.0 1.2 0% 4% 20% 0% 0% 12/ 14/ 0/ 0/ 0/ 32 1/ 3 C--VM--I--- 46%/ 73%[16] 48%[ 2] 0.6/ 3.5 246.0/ 23.0 107.6K/ 3.7K 172.5K/ 8.3K 2.3K/ 1.1K 282.4K/ 11.0K 0.0B/ 0.0B 434.0M/434.0M 0.0B/ 0.0B 434.0M/434.0M
2026/02/03 09:47:00 185.9 578.9 4.91/529.39 0.00/4342.92 742 3943.92% 42.16/177.61 0.88/ 0.36 12.4 1.2 0% 5% 22% 0% 0% 12/ 14/ 0/ 0/ 0/ 32 1/ 2 C---M--I--- 42%/ 66%[61] 45%[ 6] 0.5/ 3.1 244.5/ 23.5 77.2K/ 7.3K 125.9K/ 10.1K 2.5K/388.0B 205.6K/ 17.7K 0.0B/ 0.0B 479.4M/479.4M 0.0B/ 0.0B 479.4M/479.4M
2026/02/03 09:57:00 130.4 384.7 4.52/453.07 0.00/3358.90 521 3965.19% 12.77/124.54 1.15/ 0.34 29.9 1.4 0% 4% 20% 0% 0% 12/ 11/ 0/ 0/ 0/ 32 1/ 3 C--VM--I--- 38%/ 63%[61] 42%[ 8] 0.6/ 3.3 232.0/ 33.0 68.9K/ 4.7K 117.6K/ 13.8K 729.0B/ 17.0B 187.2K/ 18.5K 0.0B/ 0.0B 497.7M/497.7M 0.0B/ 0.0B 497.7M/497.7M
2026/02/03 10:07:00 225.1 543.9 4.56/535.18 0.00/4603.02 1035 3976.73% 15.48/214.93 1.34/ 0.35 24.3 1.5 1% 5% 21% 0% 0% 12/ 10/ 0/ 0/ 0/ 32 1/ 1 C--VM--I--- 42%/ 65%[63] 44%[ 5] 0.9/ 4.3 243.0/ 10.0 73.7K/ 9.4K 122.6K/ 12.8K 999.0B/336.0B 197.3K/ 22.6K 0.0B/ 0.0B 494.2M/494.2M 0.0B/ 0.0B 494.2M/494.2M
2026/02/03 10:17:00 611.0 656.2 5.10/333.18 0.00/3289.09 2422 4020.14% 167.55/584.37 0.63/ 0.38 2.2 2.2 1% 5% 21% 0% 0% 12/ 16/ 0/ 0/ 0/ 32 1/ 3 C---M--I--- 49%/ 69%[61] 47%[ 7] 0.7/ 0.9 248.5/ 4.5 80.2K/ 1.1K 146.0K/ 2.5K 16.9K/ 2.1K 243.1K/790.0B 0.0B/ 0.0B 481.7M/481.7M 0.0B/ 0.0B 481.7M/481.7M
2026/02/03 10:27:00 488.7 549.5 2.67/206.53 0.00/572.18 1901 4043.06% 141.03/467.35 0.58/ 0.36 2.6 1.9 0% 0% 15% 0% 0% 12/ 10/ 0/ 0/ 0/ 32 1/ 1 C--VM--I--- 41%/ 71%[61] 40%[12] 0.6/ 1.4 245.0/ 11.0 61.2K/ 7.5K 119.5K/ 10.0K 12.3K/ 3.9K 193.0K/ 21.4K 0.0B/ 0.0B 505.2M/505.2M 0.0B/ 0.0B 505.2M/505.2M
2026/02/03 10:37:00 555.4 329.6 2.05/164.31 0.00/468.37 2140 4049.55% 7.98/530.11 2.56/ 0.29 44.4 1.6 0% 0% 16% 0% 0% 12/ 12/ 0/ 0/ 0/ 0 1/ 1 C--VM--I--- 34%/ 65%[7] 33%[ 2] 0.4/ 2.3 198.0/ 7.0 58.7K/ 2.6K 101.9K/492.0B 413.0B/ 48.0B 161.0K/ 2.0K 0.0B/ 0.0B 516.6M/516.6M 0.0B/ 0.0B 516.6M/516.6M
2026/02/03 10:47:00 377.3 296.0 0.00/ 0.20 0.00/ 0.25 1547 4060.35% 7.37/360.23 2.15/ 0.28 42.7 1.5 0% 0% 0% 0% 1% 11/ 11/ 0/ 0/ 0/ 0 1/ 2 C---M--I--- 26%/ 59%[16] 40%[ 2] 0.9/ 3.0 192.5/ 12.5 21.6K/ 7.3K 88.0K/ 8.1K 391.0B/ 9.0B 109.9K/ 15.3K 0.0B/ 0.0B 388.8M/388.8M 0.0B/ 0.0B 388.8M/388.8M
2026/02/03 10:57:00 587.5 268.6 0.00/ 0.00 0.00/ 0.00 2543 4169.14% 5.92/560.99 3.35/ 0.26 50.6 1.9 0% 0% 15% 0% 1% 8/ 10/ 0/ 0/ 0/ 0 1/ 1 C--VM--I--- 19%/ 44%[16] 77%[ 2] 0.8/ 1.4 192.5/ 14.5 33.6K/ 4.4K 78.5K/ 6.7K 298.0B/ 4.0B 112.4K/ 11.1K 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B
2026/02/03 11:07:00 577.8 399.1 0.00/ 0.00 0.00/ 0.00 2707 4325.07% 18.08/551.77 1.53/ 0.28 14.1 1.4 0% 0% 17% 0% 1% 6/ 1/ 0/ 0/ 0/ 0 1/ 1 C--VM--I--- 19%/ 52%[12] 77%[10] 0.9/ 2.0 173.5/ 6.5 32.3K/ 12.7K 63.7K/ 12.2K 1.1K/504.0B 97.0K/ 24.4K 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B
2026/02/03 11:17:00 472.8 639.6 0.39/ 20.35 0.00/667.53 2202 4504.55% 5.88/451.60 2.69/ 0.28 1.0 1.8 0% 3% 18% 0% 1% 6/ 0/ 0/ 0/ 0/ 0 1/ 0 C---M--I--- 20%/ 40%[61] 75%[ 2] 0.6/ 1.4 178.5/ 2.5 31.8K/ 1.1K 47.5K/ 2.5K 357.0B/196.0B 79.6K/ 3.4K 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B
2026/02/03 11:27:00 382.2 189.9 0.00/ 0.00 0.00/ 0.00 1869 4685.39% 61.04/365.38 0.77/ 0.30 3.0 1.1 0% 2% 18% 0% 1% 6/ 2/ 0/ 0/ 0/ 0 1/ 1 C--VM--I--- 20%/ 54%[16] 75%[ 2] 0.4/ 1.3 180.0/ 2.0 21.9K/863.0B 57.3K/ 3.3K 3.7K/740.0B 82.9K/ 4.9K 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B
2026/02/03 11:37:00 368.0 148.0 0.00/ 0.00 0.00/ 0.00 1786 4847.44% 64.57/351.79 0.82/ 0.30 1.4 1.2 1% 1% 17% 0% 0% 2/ 0/ 0/ 0/ 0/ 0 1/ 0 C--VM--I--- 19%/ 61%[16] 76%[ 2] 0.5/ 2.3 158.5/ 1.5 21.0K/ 3.8K 31.8K/ 4.1K 4.0K/402.0B 56.8K/ 8.3K 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B
2026/02/03 11:47:00 42.4 12.2 0.04/ 2.04 0.00/ 49.73 165 4946.83% 9.93/ 40.48 0.70/ 0.28 1.0 1.4 1% 5% 21% 0% 2% 0/ 0/ 0/ 0/ 0/ 0 0/ 0 C--VM--I--- 16%/ 60%[7] 64%[ 2] 0.4/ 7.0 153.5/ 2.5 2.9K/360.0B 13.7K/501.0B 731.0B/142.0B 17.3K/718.0B 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B 0.0B/ 0.0B
2026/02/03 11:57:00 0.4 49.3 0.00/ 0.00 0.00/ 0.00 10 4950.36% 11.61/ 0.46 0.36/ 5.37 1.0 1.3 0% 2% 22% 1% 1% 0/ 0/ 0/ 0/ 0/ 0 0/ 0 C--VM--I--L 15%/ 78%[5] 74%[ 2] 0.8/ 5.8 156.0/ 2.0 52.0B/ 4.0B 17.3K/ 2.3K 747.0B/636.0B 18.1K/ 2.9K 0.0B/ 0.0B 46.3M/ 46.3M 8.2M/ 8.2M 54.4M/ 54.4MA definition of each output is provided below:
Throughput:
Read |
read throughput from the DDR (precomp) |
Write |
write throughput to the DDR (precomp) |
Repl Network |
replication network throughput in to and out of the DDR |
Repl Pre-comp |
replication precomp throughput into and out of the DDR (always zero for collection replication) |
Protocol:
ops/s |
File system protocol-level operations per second |
load % |
Load percentage (pending ops/total RPC ops *100) (NOTE: erroneous, > 100%, in some DDOS versions) |
data(MB/s) in/out |
Protocol throughput: amount of data the file system can read from and write to the kernel socket buffer |
wait(ms/MB) in/out |
The time taken to send and receive 1 MB of data from the file system to the kernel socket buffer. |
Compression:
gcomp |
global compression factor (deduplication) |
lcomp |
local compression factor |
Cache Miss: (only meaningful while reads are ongoing, for all metrics in table below, higher is worse)
thra |
Percent of "compression units" that have been read and discarded without being used. A high percent indicates cache thrashing. |
unus |
Percent of a compression (which contains multiple individual unique segments compressed together) unit's data that is unused.
A high percent indicates poor data locality (unique segments for files being read not being tightly packed together). |
ovhd |
Percent of a compression unit cache block that is unused. Compression regions are stored in fixed size (128 KB) blocks.
A high ovhd relative to unus indicates that a lot of space is wasted due to cache block fragmentation.
In the ideal case, ovhd == unus |
data |
Percent of data segment lookups that miss in the cache. A high percent indicates poor data prefetching. |
meta |
Percent of metadata segment lookups that miss in the cache. For each data access, a metadata lookup is performed first followed by a data lookup.
A high percent indicates poor metadata prefetching. |
Streams: (number of active external streams, streams kept between the DD and the backup applications)
rd |
active external read streams |
wr |
active external write streams |
r+ |
reopened read file streams in the past 30 seconds; streams are reopened when exhausting the supported stream allocation |
w+ |
reopened write file streams in the past 30 seconds; streams are reopened when exhausting the supported stream allocation |
Repl In |
MTree and BOOST replication streams for incoming replication to the DD |
Repl Out |
MTree and BOOST replication streams for outgoing replication from the DD |
MTree Active: (number of running MTrees for read and write)
rd |
Combined number of file system MTrees being used for ongoing file reads (restores) |
wr |
Combined number of file system MTrees being used for ongoing file writes (backups) |
State: (important background activity):
C |
Cleaning (either Active or Cloud Tier) |
D |
Disk reconstruction |
B |
MNC Rebalance |
V |
Verification |
M |
Fingerprint Merge |
S |
Summary Vector Checkpoint |
F |
Data Movement to Cloud Unit |
I |
Data Integrity |
| P | Physical Capacity Reporting (PCR) |
Utilization:
cpu |
average CPU utilization, and utilization for the busiest CPU (which ID is shown in brackets) |
disk |
disk I/O % utilization for the busiest disks. Drive index in brackets cannot be mapped to a given disk. |
Latency:
avg/std |
The average and standard deviation of the response time from the "ddfs" process when servicing all protocol requests, excluding the time to receive or send the request or reply. Higher values indicate that the "ddfs" process may be overwhelmed. |
SS LOAD BALANCE (user/repl): internal Segment Store metrics for user workloads, only meaningful for Data Domain Engineering
stream |
The number of open streams |
prefetch |
The number/percentage of prefetch requests |
rd |
The number of read requests |
wr |
The number of write requests |
tot |
The total number of requests |
SS LOAD BALANCE (gc): internal Segment Store metrics for clean and garbage collection (GC), only meaningful for Data Domain Engineering
prefetch |
Prefetch processes |
rd |
Read processes. |
wr |
Write processes. |
tot |
The total number of GC processes |
Affected Products
Data DomainArticle Properties
Article Number: 000009792
Article Type: How To
Last Modified: 19 Jun 2026
Version: 9
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