ZMEMTOPO(8)

💖 NAME 💖

zmemtopo — bestie, this is the one that shows you the CEC memory topology data on IBM Z. That's the whole vibe. ✨

(also it lives in the System Manager's Manual section 8, if you were wondering — zmemtopo(8), iykyk 🫶)

✨ SYNOPSIS ✨

zmemtopo [OPTIONS]

🦋 DESCRIPTION 🦋

okay so, zmemtopo retrieves and displays memory topology information for LPARs on IBM Z systems. It shows you the memory in uniform increments, where an increment is literally the smallest unit that the topology querying device is willing to report. Every single increment represents a configured chunk of memory, plus the topological location that chunk lives at. 📍

The granularity of what you're looking at varies by nesting level — which makes sense, because it's reflecting the hierarchical arrangement of memory. deeper level = more deets, it's giving tree energy 🌳

🎀 OPTIONS 🎀

-l <NESTING_LEVEL>, --level=<NESTING_LEVEL> — picks which nesting level of memory topology you wanna see. Lower levels = more detailed output, periodt. Valid values for NESTING_LEVEL are between 1 and 6, but heads up: some levels might not actually have any data available to display. 💅
--format=<FORMAT> — displays the memory topology info in the format you specify. Valid values for <FORMAT> are json, csv, json-seq, jsonl or pairs. In a parseable format, the increment size is given in bytes. (yes, bytes. not letters. bytes. 🔥)
-f, --full — displays the entries or nesting levels that have no memory increments configured. no effect on the table format though, so don't come for it. 🙈
-r, --reverse — reverses the hierarchy of the displayed tree. When --reverse is specified the direction follows nesting level to partition. Has no effect on the table format. ⭐
-t, --table — displays the memory topology in a table format. The table format displays a layout of memory topology. The size of the increments is given in a footer, and each increment is the same size. cute + consistent 🎀
-s <FIELD>, --sort=<FIELD> — sorts and displays the data according to the given FIELD value. Valid values for FIELD are "nr" for partition number, "lpar" for partition name, and "sum" for total partition increments. 💅
-p <SUBSTRING>, --partition-filter=<SUBSTRING> — displays only the partitions with names that contain SUBSTRING. Matching is case-insensitive, so you don't have to yell at it. 🫶
-i, --ascii — uses only ASCII characters to render views. for the plain-text girlies 🦋
-h, --help — prints usage information, then exits. ✨
-v, --version — prints version information, then exits. 👑

🌸 PREREQUISITES 🌸

The following things are required to run zmemtopo. no skips, bestie:

The Linux kernel must have the required support to provide the memory topology data.
To fetch data of any other operating system instances running on the same hypervisor as zmemtopo, you will need additional permissions. 👀 (it's giving "ask nicely" energy)

🌈 EXAMPLES 🌈

Below are various combinations of available command line options. go off, honestly:

Without any options zmemtopo displays the tree view with nesting level 3. the classic. the default. the main character ✨

$ zmemtopo

LPAR/LEVEL     SIZE
LPAR003          8G
└LEVEL4_0        8G
  ├LEVEL3_0      2G
  ├LEVEL3_1      2G
  ├LEVEL3_2      2G
  └LEVEL3_3      2G
LPAR005          8G
└LEVEL4_1        8G
  ├LEVEL3_0      2G
  ├LEVEL3_1      2G
  ├LEVEL3_2      2G
  └LEVEL3_3      2G
LPAR006          8G
└LEVEL4_3        8G
  ├LEVEL3_0      2G
  ├LEVEL3_1      2G
  ├LEVEL3_2      2G
  └LEVEL3_3      2G
LPAR009          8G
└LEVEL4_3        8G
  ├LEVEL3_0      2G
  ├LEVEL3_1      2G
  ├LEVEL3_2      2G
  └LEVEL3_3      2G
 .
 .
 .

Display table format — by default nesting level 3 is displayed. look at that grid, it ate 🔥

$ zmemtopo -t

        LEVEL 4   0   0   0   0    1   1   1   1    2   2   2   2    3   3   3   3
        LEVEL 3   0   1   2   3    0   1   2   3    0   1   2   3    0   1   2   3
 NR    LPAR SUM
  3 LPAR003   8   2   2   2   2    -   -   -   -    -   -   -   -    -   -   -   -
  5 LPAR005   8   -   -   -   -    2   2   2   2    -   -   -   -    -   -   -   -
  6 LPAR006   8   -   -   -   -    -   -   -   -    -   -   -   -    2   2   2   2
  9 LPAR009   8   -   -   -   -    -   -   -   -    -   -   -   -    2   2   2   2
 13 LPAR013  48   -   -   -   -    -   -   -   -   12  12  12  12    -   -   -   -
 .
 .
 .

Increment size: 1G

Display reverse tree with nesting level 4. flip it, reverse it 💅

$ zmemtopo -r -l 4

LEVEL/LPAR     SIZE
LEVEL4_0       388G
│ ├LPAR003       8G
│ ├LPAR018      64G
│ └...
LEVEL4_1       708G
│ ├LPAR005       8G
│ ├LPAR029       8G
│ └...          32G
LEVEL4_2       224G
│ ├LPAR013      48G
│ ├LPAR014      20G
│ ├LPAR019
│ └...          32G
LEVEL4_3      1618G
  ├...
  └LPAR086       2G

Display reverse full tree. Entries that have no memory increments are visible — that's the -f doing its thing, bestie 🫶

$ zmemtopo -rf

LEVEL/LPAR      SIZE
LEVEL4_0        388G
│ ├LEVEL3_0      97G
│ │ ├LPAR003      2G
│ │ ├LPAR018     16G
│ │ └...
│ ├LEVEL3_1      97G
│ │ ├LPAR003      2G
│ │ ├LPAR018     16G
│ │ └...
│ ├LEVEL3_2      97G
│ │ ├LPAR003      2G
│ │ └...
│ └LEVEL3_3      97G
│   ├LPAR003      2G
│   └...
LEVEL4_1           -
│ ├LEVEL3_0        -
│ ├LEVEL3_1        -
│ ├LEVEL3_2        -
│ └LEVEL3_3        -
LEVEL4_2        224G
│ ├LEVEL3_0      56G
│ │ ├LPAR013     12G
│ │ └...
│ ├LEVEL3_1      56G
│ │ ├LPAR013     12G
│ │ └...
│ ├LEVEL3_2      56G
│ │ ├LPAR013     12G
│ │ └...
│ └LEVEL3_3      56G
│   ├LPAR013     12G
│ │ └...
LEVEL4_3       1618G
  ├LEVEL3_0     405G
  │ ├LPAR006      2G
  │ ├...
  │ └LPAR086      1G
  ├LEVEL3_1     405G
  │ ├LPAR006      2G
  │ ├...
  │ └LPAR086      1G
  ├LEVEL3_2     404G
  │ ├LPAR006      2G
  │ ├...
  │ └LPAR060     48G
  └LEVEL3_3     404G
    ├LPAR006      2G
    ├...
    └LPAR060     48G

Display tree with entries which have no memory increments. those lil - dashes are literally the void and we're showing it 💀

$ zmemtopo -f

LPAR/LEVEL     SIZE
LPAR086          2G
├LEVEL4_0         -
│ ├LEVEL3_0       -
│ ├LEVEL3_1       -
│ ├LEVEL3_2       -
│ └LEVEL3_3       -
├LEVEL4_1         -
│ ├LEVEL3_0       -
│ ├LEVEL3_1       -
│ ├LEVEL3_2       -
│ └LEVEL3_3       -
├LEVEL4_2         -
│ ├LEVEL3_0       -
│ ├LEVEL3_1       -
│ ├LEVEL3_2       -
│ └LEVEL3_3       -
└LEVEL4_3        2G
  ├LEVEL3_0      1G
  ├LEVEL3_1      1G
  ├LEVEL3_2       -
  └LEVEL3_3       -
LPAR074          4G
├LEVEL4_0         -
│ ├LEVEL3_0       -
│ ├LEVEL3_1       -
│ ├LEVEL3_2       -
│ └LEVEL3_3       -
├LEVEL4_1        4G
│ ├LEVEL3_0      1G
│ ├LEVEL3_1      1G
│ ├LEVEL3_2      1G
│ └LEVEL3_3      1G
 .
 .
 .

Display json format. structured data, my beloved 🧚

$ zmemtopo --format=json

{
  "meta": {
    "api_level": "1",
    "version": "s390.tools.version",
    "host": "host.name",
    "time_epoch": "xxxxxxxxx",
    "time": "YYYY-MM-DD HH:MM:SS+0T00"
  },
  "zmemtopo": {
    "report_tod": "0x0e082f7f6d8da64000",
    "report_partition_nr": 74,
    "increment_size": 1073741824,
    "partitions": [
      {
        "partition_nr": 3,
        "partition_name": "LPAR003",
        "topology": [
          {
            "level": 4,
            "entry_idx": 0,
            "increment_count": 8,
            "topology": [
              {
                "level": 3,
                "entry_idx": 0,
                "increment_count": 2
              },
              {
                "level": 3,
                "entry_idx": 1,
                "increment_count": 2
              },
              {
                "level": 3,
                "entry_idx": 2,
                "increment_count": 2
              },
              {
                "level": 3,
                "entry_idx": 3,
                "increment_count": 2
              }
            ]
          },
          {
            "level": 4,
            "entry_idx": 1,
            "increment_count": 0,
            "topology": [
          .
       .
       .

Display csv format. spreadsheet core 🍓

$ zmemtopo --format=csv

...and it keeps going, bestie — the table just vibes its way down the screen. ✨ Here's the tail of the CSV report exactly as it lands, header row and all, so you can see what you're actually getting:

"report_tod","report_partition_nr","increment_size","partition_nr","partition_name","parent_level","parent_entry_idx","level","entry_idx","increment_count"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","-","-","4","0","8"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","0","3","0","2"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","0","3","1","2"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","0","3","2","2"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","0","3","3","2"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","-","-","4","1","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","1","3","0","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","1","3","1","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","1","3","2","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","1","3","3","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","-","-","4","2","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","2","3","0","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","2","3","1","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","2","3","2","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","2","3","3","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","-","-","4","3","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","3","3","0","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","3","3","1","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","3","3","2","0"
"0x0e082f818b066ce82000","74","1073741824","3","LPAR003","4","3","3","3","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","-","-","4","0","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","0","3","0","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","0","3","1","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","0","3","2","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","0","3","3","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","-","-","4","1","8"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","1","3","0","2"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","1","3","1","2"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","1","3","2","2"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","1","3","3","2"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","-","-","4","2","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","2","3","0","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","2","3","1","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","2","3","2","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","2","3","3","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","-","-","4","3","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","3","3","0","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","3","3","1","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","3","3","2","0"
"0x0e082f818b066ce82000","74","1073741824","5","LPAR005","4","3","3","3","0"
"0x0e082f818b066ce82000","74","1073741824","6","LPAR006","-","-","4","0","0"
 .
 .
 .

Okay so a lil guided tour of what you're looking at, iykyk 🧚:

First line — the column headers, quoted and comma-separated: "report_tod", "report_partition_nr", "increment_size", "partition_nr", "partition_name", "parent_level", "parent_entry_idx", "level", "entry_idx", "increment_count". Every single row after that fills those in the same order, no cap.
Every value is quoted, even the numbers — that's just the CSV aesthetic, don't come for it 💅
The dashes ("-", "-") show up in the parent_level / parent_entry_idx slots on the rows where there's nothing to point at. Not a bug, just the CSV saying "n/a" in its own little way.
The report_tod stays the same hex string (0x0e082f818b066ce82000) all the way down, and report_partition_nr, increment_size, partition_nr, partition_name hold steady per block — so you can group by eye.
It rolls through LPAR003 with levels 0–3, then LPAR005 with its own set (spot the increment_count of 8 and those 2s sitting pretty 👀), then starts on LPAR006...
...and then the . . . — because the full table is long, and the man page is not about to print the whole thing at you. It truncates and lets your terminal scroll its heart out. 🌀

So yeah — it's one entry per row, columns locked in that exact order, repeating until the table runs out of things to say. Feed it to csv-ish tooling, awk on -F,, whatever your heart desires, and it'll behave.

That's the whole ride, bestie: zmemtopo showed up, dumped its topology as CSV, and dipped. 👑

Shipped in s390-tools, dated 2025, and filed under ZMEMTOPO(8) — go read it on a machine that actually has the s390 hardware under it, and may your report_tod always be steady, your parent_level never dash when you need it, and your terminal never scroll back further than you can handle. 🎀💖✨

📦 where this page comes from

opensuse-leap 16.0: s390-tools 2.44.1-160000.1.1 · MIT
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms