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/c3963210ebCloses#8230
Porting Notes:
* Additional changes to recv_rename_impl() were required due to
encryption code not being merged in OpenZFS yet.
* libzfs_core python bindings (pyzfs) were updated to fully support
both lzc_rename() and lzc_destroy()
Authored by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: loli10K <ezomori.nozomu@gmail.com>
OpenZFS-issue: https://www.illumos.org/issues/9630
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/049ba63Closes#8207
Move strlcat() and strlcpy() from .c source files in to the libspl
string.h header. By changing these compatibility functions to static
inline functions they can included as needed without requiring linking
with the libspl.so library.
Remove strnlen() which is barely used in the source, and has been
provided by glibc since v2.10.
Finally, convert four instances of strncpy() to strlcpy() in
libzfs_input_check.c which were causing build warnings when compiling
with gcc 8.2.1. For example:
libzfs_input_check.c: In function ‘zfs_destroy’:
libzfs_input_check.c:651:9: error: ‘strncpy’ specified bound \
4096 equals destination size [-Werror=stringop-truncation]
(void) strncpy(zc.zc_name, dataset, sizeof (zc.zc_name));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8116
We want newer versions of libzfs_core to run against an existing
zfs kernel module (i.e. a deferred reboot or module reload after
an update).
Programmatically document, via a zfs_ioc_key_t, the valid arguments
for the ioc commands that rely on nvpair input arguments (i.e. non
legacy commands from libzfs_core). Automatically verify the expected
pairs before dispatching a command.
This initial phase focuses on the non-legacy ioctls. A follow-on
change can address the legacy ioctl input from the zfs_cmd_t.
The zfs_ioc_key_t for zfs_keys_channel_program looks like:
static const zfs_ioc_key_t zfs_keys_channel_program[] = {
{"program", DATA_TYPE_STRING, 0},
{"arg", DATA_TYPE_UNKNOWN, 0},
{"sync", DATA_TYPE_BOOLEAN_VALUE, ZK_OPTIONAL},
{"instrlimit", DATA_TYPE_UINT64, ZK_OPTIONAL},
{"memlimit", DATA_TYPE_UINT64, ZK_OPTIONAL},
};
Introduce four input errors to identify specific input failures
(in addition to generic argument value errors like EINVAL, ERANGE,
EBADF, and E2BIG).
ZFS_ERR_IOC_CMD_UNAVAIL the ioctl number is not supported by kernel
ZFS_ERR_IOC_ARG_UNAVAIL an input argument is not supported by kernel
ZFS_ERR_IOC_ARG_REQUIRED a required input argument is missing
ZFS_ERR_IOC_ARG_BADTYPE an input argument has an invalid type
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes#7780
George Wilson
Andriy Gapon
Brian Behlendorf
Don Brady