Commit 367784a6 authored by Niklas Cassel's avatar Niklas Cassel Committed by Tomasz Zawadzki
Browse files

bdev/fio_plugin: update README.md and add example zbd config 



Update README.md with information specific to zoned block devices.
Additionally, add an example config that can be used to test the
--zonemode=zbd fio option using the virtual zoned block device
SPDK module on top of a Malloc bdev.

Signed-off-by: default avatarNiklas Cassel <niklas.cassel@wdc.com>
Change-Id: I68bbc07ab70ad1ce8e38abc91dd8c15c49f90656
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/7758


Community-CI: Broadcom CI
Community-CI: Mellanox Build Bot
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
parent e415c253

examples/bdev/fio_plugin/README.md

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@@ -71,3 +71,49 @@ engine's full path via the ioengine parameter - LD_PRELOAD is recommended to avo 
When testing random workloads, it is recommended to set norandommap=1.  fio's random map

processing consumes extra CPU cycles which will degrade performance over time with

the fio_plugin since all I/O are submitted and completed on a single CPU core.



# Zoned Block Devices



SPDK has a zoned block device API (bdev_zone.h) which currently supports Open-channel SSDs,

NVMe Zoned Namespaces (ZNS), and the virtual zoned block device SPDK module.



If you wish to run fio against a SPDK zoned block device, you can use the fio option:



    zonemode=zbd



It is recommended to use a fio version newer than version 3.26, if using --numjobs > 1.

If using --numjobs=1, fio version >= 3.23 should suffice.



See zbd_example.fio in this directory for a zoned block device example config.



## Maximum Open Zones



Most zoned block devices have a resource constraint on the amount of zones which can be in an opened

state at any point in time. It is very important to not exceed this limit.



You can control how many zones fio will keep in an open state by using the

``--max_open_zones`` option.



## Maximum Active Zones



Zoned block devices may also have a resource constraint on the number of zones that can be active at

any point in time. Unlike ``max_open_zones``, fio currently does not manage this constraint, and

there is thus no option to limit it either.



Since the max active zones limit (by definition) has to be greater than or equal to the max active

zones limit, the easiest way to work around that fio does not manage this constraint, is to start

with a clean state each run (except for read-only workloads), by resetting all zones before fio

starts running its jobs by using the engine option:



    --initial_zone_reset=1



## Zone Append



When running fio against a zoned block device you need to specify --iodepth=1 to avoid

"Zone Invalid Write: The write to a zone was not at the write pointer." I/O errors.

However, if your zoned block device supports Zone Append, you can use the engine option:



    --zone_append=1



To send zone append commands instead of write commands to the zoned block device.

When using zone append, you will be able to specify a --iodepth greater than 1.

examples/bdev/fio_plugin/bdev_zoned.json

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{

  "subsystems": [

    {

      "subsystem": "bdev",

      "config": [

        {

          "method": "bdev_malloc_create",

          "params": {

            "name": "Malloc0",

            "num_blocks": 2097152,

            "block_size": 512

          }

        },

        {

          "method": "bdev_zone_block_create",

          "params": {

            "base_bdev": "Malloc0",

            "name": "Zone0",

            "zone_capacity": 262144,

            "optimal_open_zones": 8

          }

        }

      ]

    }

  ]

}

examples/bdev/fio_plugin/zbd_example.fio

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[global]

ioengine=spdk_bdev

spdk_json_conf=./examples/bdev/fio_plugin/bdev_zoned.json

thread=1

direct=1

time_based

runtime=10

rw=randwrite

bs=16K

zonemode=zbd

max_open_zones=8

initial_zone_reset=1

zone_append=1

iodepth=64



[test]

filename=Zone0

numjobs=1