mirror_zfs/tests
George Wilson 619f097693 OpenZFS 9102 - zfs should be able to initialize storage devices
PROBLEM
========

The first access to a block incurs a performance penalty on some platforms
(e.g. AWS's EBS, VMware VMDKs). Therefore we recommend that volumes are
"thick provisioned", where supported by the platform (VMware). This can
create a large delay in getting a new virtual machines up and running (or
adding storage to an existing Engine). If the thick provision step is
omitted, write performance will be suboptimal until all blocks on the LUN
have been written.

SOLUTION
=========

This feature introduces a way to 'initialize' the disks at install or in the
background to make sure we don't incur this first read penalty.

When an entire LUN is added to ZFS, we make all space available immediately,
and allow ZFS to find unallocated space and zero it out. This works with
concurrent writes to arbitrary offsets, ensuring that we don't zero out
something that has been (or is in the middle of being) written. This scheme
can also be applied to existing pools (affecting only free regions on the
vdev). Detailed design:
        - new subcommand:zpool initialize [-cs] <pool> [<vdev> ...]
                - start, suspend, or cancel initialization
        - Creates new open-context thread for each vdev
        - Thread iterates through all metaslabs in this vdev
        - Each metaslab:
                - select a metaslab
                - load the metaslab
                - mark the metaslab as being zeroed
                - walk all free ranges within that metaslab and translate
                  them to ranges on the leaf vdev
                - issue a "zeroing" I/O on the leaf vdev that corresponds to
                  a free range on the metaslab we're working on
                - continue until all free ranges for this metaslab have been
                  "zeroed"
                - reset/unmark the metaslab being zeroed
                - if more metaslabs exist, then repeat above tasks.
                - if no more metaslabs, then we're done.

        - progress for the initialization is stored on-disk in the vdev’s
          leaf zap object. The following information is stored:
                - the last offset that has been initialized
                - the state of the initialization process (i.e. active,
                  suspended, or canceled)
                - the start time for the initialization

        - progress is reported via the zpool status command and shows
          information for each of the vdevs that are initializing

Porting notes:
- Added zfs_initialize_value module parameter to set the pattern
  written by "zpool initialize".
- Added zfs_vdev_{initializing,removal}_{min,max}_active module options.

Authored by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Wren Kennedy <john.kennedy@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: loli10K <ezomori.nozomu@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Richard Lowe <richlowe@richlowe.net>
Signed-off-by: Tim Chase <tim@chase2k.com>
Ported-by: Tim Chase <tim@chase2k.com>

OpenZFS-issue: https://www.illumos.org/issues/9102
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c3963210eb
Closes #8230
2019-01-07 10:37:26 -08:00
..
runfiles OpenZFS 9102 - zfs should be able to initialize storage devices 2019-01-07 10:37:26 -08:00
test-runner test-runner: python3 support 2019-01-06 10:39:41 -08:00
zfs-tests OpenZFS 9102 - zfs should be able to initialize storage devices 2019-01-07 10:37:26 -08:00
Makefile.am Add the ZFS Test Suite 2016-03-16 13:46:16 -07:00
README.md Update tests/README.md and fix markdown 2018-05-15 09:01:28 -07:00

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
  1. 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 sciprt 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.

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 instread 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/.

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

-r RUNFILE  Run tests in RUNFILE (default: 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.

  1. 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