While we initially allowed you to set your ashift as large as 17
(SPA_MAXBLOCKSIZE) that is actually unsafe. What wasn't considered
at the time is that each uberblock written to the vdev label ring
buffer will be of this size. Now the buffer is statically sized
to 128k and we need to be able to fit several uberblocks in it.
With a large ashift that becomes a problem.
Therefore I'm reducing the maximum configurable ashift value to 12.
This is large enough for the 4k sector drives and small enough that
we can still keep the most recent 32 uberblock in the vdev label
ring buffer.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#425
Some disks with internal sectors larger than 512 bytes (e.g., 4k) can
suffer from bad write performance when ashift is not configured
correctly. This is caused by the disk not reporting its actual sector
size, but a sector size of 512 bytes. The drive may behave this way
for compatibility reasons. For example, the WDC WD20EARS disks are
known to exhibit this behavior.
When creating a zpool, ZFS takes that wrong sector size and sets the
"ashift" property accordingly (to 9: 1<<9=512), whereas it should be
set to 12 for 4k sectors (1<<12=4096).
This patch allows an adminstrator to manual specify the known correct
ashift size at 'zpool create' time. This can significantly improve
performance in certain cases. However, it will have an impact on your
total pool capacity. See the updated ashift property description
in the zpool.8 man page for additional details.
Valid values for the ashift property range from 9 to 17 (512B-128KB).
Additionally, you may set the ashift to 0 if you wish to auto-detect
the sector size based on what the disk reports, this is the default
behavior. The most common ashift values are 9 and 12.
Example:
zpool create -o ashift=12 tank raidz2 sda sdb sdc sdd
Closes#280
Original-patch-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
zpool status displays abbreviated vdev names without leading path components
and, in the case of whole disks, without partition information. Also, the
zpool subcommands 'create' and 'add' support using shorthand devices names
without qualified paths. Prior to this change, however, removing a device
generally required specifying its name as it is stored in the vdev label. So
while zpool status might list a cache disk with a name like A16, removing it
would require a full path such as /dev/disk/zpool/A16-part1, which is
non-intuitive.
This change adds support for shorthand device names with the remove subcommand
so one can simply type, for example,
zpool remove tank A16
A consequence of this change is that including the partition information when
removing a whole-disk vdev now results in an error. While this is arguably the
correct behavior, it is a departure from how zpool previously worked in this
project.
This change removes the only reference to ctd_check_path(), so that function is
also removed to avoid compiler warnings.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Under Solaris, the slice number is chopped off when displaying the device name
if the vdev is a whole disk. Under Linux we should similarly discard the
partition number. This commit adds the logic to perform the name truncation
for devices ending in -partX, XpX, or X, where X is a string of digits. The
second case handles devices like md0p0. The third case is limited to scsi and
ide disks, i.e. those beginning with "sd" or "hd", in order to avoid stripping
the number from names like "loop0".
This commit removes the Solaris-specific code for removing slices, since we no
longer reasonably expect our changes to be merged in upstream. The partition
stripping code was moved off to a helper function to improve readability.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Top-level vdev names in zpool status output should follow a <type-id> naming
convention. In the case of raidz devices, the type portion of the name was
missing.
This commit fixes a bug in zpool_vdev_name() where in this snprintf call
(void) snprintf(buf, sizeof (buf), "%s-%llu", path,
(u_longlong_t)id);
buf and path may point to the same location. The result is that buf ends up
containing only the "-id" part. This only occurred for raidz devices because
the code for appending the parity level to the type string stored its result in
buf then set path to point there. To fix this we allocate a new temporary
buffer on the stack instead of reusing buf.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#57
This topic branch contains all the changes needed to integrate the user
side zfs tools with Linux style devices. Primarily this includes fixing
up the Solaris libefi library to be Linux friendly, and integrating with
the libblkid library which is provided by e2fsprogs.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This topic branch leverages the Solaris style FMA call points
in ZFS to create a user space visible event notification system
under Linux. This new system is called zevent and it unifies
all previous Solaris style ereports and sysevent notifications.
Under this Linux specific scheme when a sysevent or ereport event
occurs an nvlist describing the event is created which looks almost
exactly like a Solaris ereport. These events are queued up in the
kernel when they occur and conditionally logged to the console.
It is then up to a user space application to consume the events
and do whatever it likes with them.
To make this possible the existing /dev/zfs ABI has been extended
with two new ioctls which behave as follows.
* ZFS_IOC_EVENTS_NEXT
Get the next pending event. The kernel will keep track of the last
event consumed by the file descriptor and provide the next one if
available. If no new events are available the ioctl() will block
waiting for the next event. This ioctl may also be called in a
non-blocking mode by setting zc.zc_guid = ZEVENT_NONBLOCK. In the
non-blocking case if no events are available ENOENT will be returned.
It is possible that ESHUTDOWN will be returned if the ioctl() is
called while module unloading is in progress. And finally ENOMEM
may occur if the provided nvlist buffer is not large enough to
contain the entire event.
* ZFS_IOC_EVENTS_CLEAR
Clear are events queued by the kernel. The kernel will keep a fairly
large number of recent events queued, use this ioctl to clear the
in kernel list. This will effect all user space processes consuming
events.
The zpool command has been extended to use this events ABI with the
'events' subcommand. You may run 'zpool events -v' to output a
verbose log of all recent events. This is very similar to the
Solaris 'fmdump -ev' command with the key difference being it also
includes what would be considered sysevents under Solaris. You
may also run in follow mode with the '-f' option. To clear the
in kernel event queue use the '-c' option.
$ sudo cmd/zpool/zpool events -fv
TIME CLASS
May 13 2010 16:31:15.777711000 ereport.fs.zfs.config.sync
class = "ereport.fs.zfs.config.sync"
ena = 0x40982b7897700001
detector = (embedded nvlist)
version = 0x0
scheme = "zfs"
pool = 0xed976600de75dfa6
(end detector)
time = 0x4bec8bc3 0x2e5aed98
pool = "zpios"
pool_guid = 0xed976600de75dfa6
pool_context = 0x0
While the 'zpool events' command is handy for interactive debugging
it is not expected to be the primary consumer of zevents. This ABI
was primarily added to facilitate the addition of a user space
monitoring daemon. This daemon would consume all events posted by
the kernel and based on the type of event perform an action. For
most events simply forwarding them on to syslog is likely enough.
But this interface also cleanly allows for more sophisticated
actions to be taken such as generating an email for a failed drive.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Brian Behlendorf
Christian Kohlschütter
Ned Bass