zfs/tests
Jason Lee 3070faa798 ZFS Interface for Accelerators (Z.I.A.)
The ZIO pipeline has been modified to allow for external,
alternative implementations of existing operations to be
used. The original ZFS functions remain in the code as
fallback in case the external implementation fails.

Definitions:
    Accelerator - an entity (usually hardware) that is
                  intended to accelerate operations
    Offloader   - synonym of accelerator; used interchangeably
    Data Processing Unit Services Module (DPUSM)
                - https://github.com/hpc/dpusm
                - defines a "provider API" for accelerator
                  vendors to set up
                - defines a "user API" for accelerator consumers
                  to call
                - maintains list of providers and coordinates
                  interactions between providers and consumers.
    Provider    - a DPUSM wrapper for an accelerator's API
    Offload     - moving data from ZFS/memory to the accelerator
    Onload      - the opposite of offload

In order for Z.I.A. to be extensible, it does not directly
communicate with a fixed accelerator. Rather, Z.I.A. acquires
a handle to a DPUSM, which is then used to acquire handles
to providers.

Using ZFS with Z.I.A.:
    1. Build and start the DPUSM
    2. Implement, build, and register a provider with the DPUSM
    3. Reconfigure ZFS with '--with-zia=<DPUSM root>'
    4. Rebuild and start ZFS
    5. Create a zpool
    6. Select the provider
           zpool set zia_provider=<provider name> <zpool>
    7. Select operations to offload
           zpool set zia_<property>=on <zpool>

The operations that have been modified are:
    - compression
        - non-raw-writes only
    - decompression
    - checksum
        - not handling embedded checksums
        - checksum compute and checksum error call the same function
    - raidz
        - generation
        - reconstruction
    - vdev_file
        - open
        - write
        - close
    - vdev_disk
        - open
        - invalidate
        - write
        - flush
        - close

Successful operations do not bring data back into memory after
they complete, allowing for subsequent offloader operations
reuse the data. This results in only one data movement per ZIO
at the beginning of a pipeline that is necessary for getting
data from ZFS to the accelerator.

When errors ocurr and the offloaded data is still accessible,
the offloaded data will be onloaded (or dropped if it still
matches the in-memory copy) for that ZIO pipeline stage and
processed with ZFS. This will cause thrashing if a later
operation offloads data. This should not happen often, as
constant errors (resulting in data movement) is not expected
to be the norm.

Unrecoverable errors such as hardware failures will trigger
pipeline restarts (if necessary) in order to complete the
original ZIO using the software path.

The modifications to ZFS can be thought of as two sets of changes:
    - The ZIO write pipeline
        - compression, checksum, RAIDZ generation, and write
        - Each stage starts by offloading data that was not
          previously offloaded
            - This allows for ZIOs to be offloaded at any point
              in the pipeline
    - Resilver
        - vdev_raidz_io_done (RAIDZ reconstruction, checksum, and
          RAIDZ generation), and write
        - Because the core of resilver is vdev_raidz_io_done, data
          is only offloaded once at the beginning of
          vdev_raidz_io_done
            - Errors cause data to be onloaded, but will not
              re-offload in subsequent steps within resilver
            - Write is a separate ZIO pipeline stage, so it will
              attempt to offload data

The zio_decompress function has been modified to allow for
offloading but the ZIO read pipeline as a whole has not, so it
is not part of the above list.

An example provider implementation can be found in
module/zia-software-provider
    - The provider's "hardware" is actually software - data is
      "offloaded" to memory not owned by ZFS
    - Calls ZFS functions in order to not reimplement operations
    - Has kernel module parameters that can be used to trigger
      ZIA_ACCELERATOR_DOWN states for testing pipeline restarts.

abd_t, raidz_row_t, and vdev_t have each been given an additional
"void *<prefix>_zia_handle" member. These opaque handles point to
data that is located on an offloader. abds are still allocated,
but their payloads are expected to diverge from the offloaded copy
as operations are run.

Encryption and deduplication are disabled for zpools with Z.I.A.
operations enabled

Aggregation is disabled for offloaded abds

RPMs will build with Z.I.A.

Signed-off-by: Jason Lee <jasonlee@lanl.gov>
2024-09-10 15:14:15 +00:00
..
runfiles ZFS Interface for Accelerators (Z.I.A.) 2024-09-10 15:14:15 +00:00
test-runner zts-report: don't crash on non-UTF-8 chars in the log (#16497) 2024-09-09 17:49:14 -07:00
zfs-tests ZFS Interface for Accelerators (Z.I.A.) 2024-09-10 15:14:15 +00:00
Makefile.am Block cloning tests. 2023-12-26 12:01:53 -08:00
README.md tests: README: note non-default mountd requirement 2022-04-01 17:57:45 -07:00

README.md

ZFS Test Suite README

1) Building and installing the ZFS Test Suite

The ZFS Test Suite runs under the test-runner framework. This framework is built along side the standard ZFS utilities and is included as part of zfs-test package. The zfs-test package can be built from source as follows:

$ ./configure
$ make pkg-utils

The resulting packages can be installed using the rpm or dpkg command as appropriate for your distributions. Alternately, if you have installed ZFS from a distributions repository (not from source) the zfs-test package may be provided for your distribution.

- Installed from source
$ rpm -ivh ./zfs-test*.rpm, or
$ dpkg -i ./zfs-test*.deb,

- Installed from package repository
$ yum install zfs-test
$ apt-get install zfs-test

2) Running the ZFS Test Suite

The pre-requisites for running the ZFS Test Suite are:

  • Three scratch disks
    • Specify the disks you wish to use in the $DISKS variable, as a space delimited list like this: DISKS='vdb vdc vdd'. By default the zfs-tests.sh script will construct three loopback devices to be used for testing: DISKS='loop0 loop1 loop2'.
  • A non-root user with a full set of basic privileges and the ability to sudo(8) to root without a password to run the test.
  • Specify any pools you wish to preserve as a space delimited list in the $KEEP variable. All pools detected at the start of testing are added automatically.
  • The ZFS Test Suite will add users and groups to test machine to verify functionality. Therefore it is strongly advised that a dedicated test machine, which can be a VM, be used for testing.
  • On FreeBSD, mountd(8) must use /etc/zfs/exports as one of its export files by default this can be done by setting zfs_enable=yes in /etc/rc.conf.

Once the pre-requisites are satisfied simply run the zfs-tests.sh script:

$ /usr/share/zfs/zfs-tests.sh

Alternately, the zfs-tests.sh script can be run from the source tree to allow developers to rapidly validate their work. In this mode the ZFS utilities and modules from the source tree will be used (rather than those installed on the system). In order to avoid certain types of failures you will need to ensure the ZFS udev rules are installed. This can be done manually or by ensuring some version of ZFS is installed on the system.

$ ./scripts/zfs-tests.sh

The following zfs-tests.sh options are supported:

-v          Verbose zfs-tests.sh output When specified additional
            information describing the test environment will be logged
            prior to invoking test-runner.  This includes the runfile
            being used, the DISKS targeted, pools to keep, etc.

-q          Quiet test-runner output.  When specified it is passed to
            test-runner(1) which causes output to be written to the
            console only for tests that do not pass and the results
            summary.

-x          Remove all testpools, dm, lo, and files (unsafe).  When
            specified the script will attempt to remove any leftover
            configuration from a previous test run.  This includes
            destroying any pools named testpool, unused DM devices,
            and loopback devices backed by file-vdevs.  This operation
            can be DANGEROUS because it is possible that the script
            will mistakenly remove a resource not related to the testing.

-k          Disable cleanup after test failure.  When specified the
            zfs-tests.sh script will not perform any additional cleanup
            when test-runner exists.  This is useful when the results of
            a specific test need to be preserved for further analysis.

-f          Use sparse files directly instead of loopback devices for
            the testing.  When running in this mode certain tests will
            be skipped which depend on real block devices.

-c          Only create and populate constrained path

-I NUM      Number of iterations

-d DIR      Create sparse files for vdevs in the DIR directory.  By
            default these files are created under /var/tmp/.
            This directory must be world-writable.

-s SIZE     Use vdevs of SIZE (default: 4G)

-r RUNFILES Run tests in RUNFILES (default: common.run,linux.run)

-t PATH     Run single test at PATH relative to test suite

-T TAGS     Comma separated list of tags (default: 'functional')

-u USER     Run single test as USER (default: root)

The ZFS Test Suite allows the user to specify a subset of the tests via a runfile or list of tags.

The format of the runfile is explained in test-runner(1), and the files that zfs-tests.sh uses are available for reference under /usr/share/zfs/runfiles. To specify a custom runfile, use the -r option:

$ /usr/share/zfs/zfs-tests.sh -r my_tests.run

Otherwise user can set needed tags to run only specific tests.

3) Test results

While the ZFS Test Suite is running, one informational line is printed at the end of each test, and a results summary is printed at the end of the run. The results summary includes the location of the complete logs, which is logged in the form /var/tmp/test_results/[ISO 8601 date]. A normal test run launched with the zfs-tests.sh wrapper script will look something like this:

$ /usr/share/zfs/zfs-tests.sh -v -d /tmp/test

--- Configuration ---
Runfile:         /usr/share/zfs/runfiles/linux.run
STF_TOOLS:       /usr/share/zfs/test-runner
STF_SUITE:       /usr/share/zfs/zfs-tests
STF_PATH:        /var/tmp/constrained_path.G0Sf
FILEDIR:         /tmp/test
FILES:           /tmp/test/file-vdev0 /tmp/test/file-vdev1 /tmp/test/file-vdev2
LOOPBACKS:       /dev/loop0 /dev/loop1 /dev/loop2
DISKS:           loop0 loop1 loop2
NUM_DISKS:       3
FILESIZE:        4G
ITERATIONS:      1
TAGS:            functional
Keep pool(s):    rpool


/usr/share/zfs/test-runner/bin/test-runner.py  -c /usr/share/zfs/runfiles/linux.run \
    -T functional -i /usr/share/zfs/zfs-tests -I 1
Test: /usr/share/zfs/zfs-tests/tests/functional/arc/setup (run as root) [00:00] [PASS]
...more than 1100 additional tests...
Test: /usr/share/zfs/zfs-tests/tests/functional/zvol/zvol_swap/cleanup (run as root) [00:00] [PASS]

Results Summary
SKIP	  52
PASS	 1129

Running Time:	02:35:33
Percent passed:	95.6%
Log directory:	/var/tmp/test_results/20180515T054509

4) Example of adding and running test-case (zpool_example)

This broadly boils down to 5 steps

  1. Create/Set password-less sudo for user running test case.
  2. Edit configure.ac, Makefile.am appropriately
  3. Create/Modify .run files
  4. Create actual test-scripts
  5. Run Test case

Will look at each of them in depth.

  • Set password-less sudo for 'Test' user as test script cannot be run as root

  • Edit file configure.ac and include line under AC_CONFIG_FILES section

      tests/zfs-tests/tests/functional/cli_root/zpool_example/Makefile
    
  • Edit file tests/runfiles/Makefile.am and add line zpool_example.

      pkgdatadir = $(datadir)/@PACKAGE@/runfiles
      dist_pkgdata_DATA = \
        zpool_example.run \
        common.run \
        freebsd.run \
        linux.run \
        longevity.run \
        perf-regression.run \
        sanity.run \
        sunos.run
    
  • Create file tests/runfiles/zpool_example.run. This defines the most common properties when run with test-runner.py or zfs-tests.sh.

      [DEFAULT]
      timeout = 600
      outputdir = /var/tmp/test_results
      tags = ['functional']
    
      tests = ['zpool_example_001_pos']
    

    If adding test-case to an already existing suite the runfile would already be present and it needs to be only updated. For example, adding zpool_example_002_pos to the above runfile only update the "tests =" section of the runfile as shown below

      [DEFAULT]
      timeout = 600
      outputdir = /var/tmp/test_results
      tags = ['functional']
    
      tests = ['zpool_example_001_pos', 'zpool_example_002_pos']
    
  • Edit tests/zfs-tests/tests/functional/cli_root/Makefile.am and add line under SUBDIRS.

      zpool_example \ (Make sure to escape the line end as there will be other folders names following)
    
  • Create new file tests/zfs-tests/tests/functional/cli_root/zpool_example/Makefile.am the contents of the file could be as below. What it says it that now we have a test case zpool_example_001_pos.ksh

      pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/cli_root/zpool_example
      dist_pkgdata_SCRIPTS = \
        zpool_example_001_pos.ksh
    
  • We can now create our test-case zpool_example_001_pos.ksh under tests/zfs-tests/tests/functional/cli_root/zpool_example/.

    # DESCRIPTION:
    #	zpool_example Test
    #
    # STRATEGY:
    #	1. Demo a very basic test case
    #
    
    DISKS_DEV1="/dev/loop0"
    DISKS_DEV2="/dev/loop1"
    TESTPOOL=EXAMPLE_POOL
    
    function cleanup
    {
    	# Cleanup
    	destroy_pool $TESTPOOL
    	log_must rm -f $DISKS_DEV1
    	log_must rm -f $DISKS_DEV2
    }
    
    log_assert "zpool_example"
    # Run function "cleanup" on exit
    log_onexit cleanup
    
    # Prep backend device
    log_must dd if=/dev/zero of=$DISKS_DEV1 bs=512 count=140000
    log_must dd if=/dev/zero of=$DISKS_DEV2 bs=512 count=140000
    
    # Create pool
    log_must zpool create $TESTPOOL $type $DISKS_DEV1 $DISKS_DEV2
    
    log_pass "zpool_example"
    
  • Run Test case, which can be done in two ways. Described in detail above in section 2.

    • test-runner.py (This takes run file as input. See zpool_example.run)
    • zfs-tests.sh. Can execute the run file or individual tests