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authorGeorge Wilson <george.wilson@delphix.com>2018-12-19 07:54:59 -0700
committerBrian Behlendorf <behlendorf1@llnl.gov>2019-01-07 10:37:26 -0800
commit619f09769393d4e0cbaa5f662362138e1c699159 (patch)
tree6a94855931e5bf9e353270c72fba43316a44baa6 /include/sys/metaslab_impl.h
parentc87db591967507de027d6bb0c683ffd09dd70105 (diff)
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
Diffstat (limited to 'include/sys/metaslab_impl.h')
-rw-r--r--include/sys/metaslab_impl.h10
1 files changed, 9 insertions, 1 deletions
diff --git a/include/sys/metaslab_impl.h b/include/sys/metaslab_impl.h
index aa1c82a02..3e32eace6 100644
--- a/include/sys/metaslab_impl.h
+++ b/include/sys/metaslab_impl.h
@@ -68,7 +68,8 @@ typedef enum trace_alloc_type {
TRACE_GROUP_FAILURE = -5ULL,
TRACE_ENOSPC = -6ULL,
TRACE_CONDENSING = -7ULL,
- TRACE_VDEV_ERROR = -8ULL
+ TRACE_VDEV_ERROR = -8ULL,
+ TRACE_INITIALIZING = -9ULL
} trace_alloc_type_t;
#define METASLAB_WEIGHT_PRIMARY (1ULL << 63)
@@ -270,6 +271,11 @@ struct metaslab_group {
uint64_t mg_failed_allocations;
uint64_t mg_fragmentation;
uint64_t mg_histogram[RANGE_TREE_HISTOGRAM_SIZE];
+
+ int mg_ms_initializing;
+ boolean_t mg_initialize_updating;
+ kmutex_t mg_ms_initialize_lock;
+ kcondvar_t mg_ms_initialize_cv;
};
/*
@@ -360,6 +366,8 @@ struct metaslab {
boolean_t ms_condense_wanted;
uint64_t ms_condense_checked_txg;
+ uint64_t ms_initializing; /* leaves initializing this ms */
+
/*
* We must hold both ms_lock and ms_group->mg_lock in order to
* modify ms_loaded.