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Diffstat (limited to 'Documentation/admin-guide/blockdev/zoned_loop.rst')
| -rw-r--r-- | Documentation/admin-guide/blockdev/zoned_loop.rst | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/Documentation/admin-guide/blockdev/zoned_loop.rst b/Documentation/admin-guide/blockdev/zoned_loop.rst index 6aa865424ac3..64277494fb36 100644 --- a/Documentation/admin-guide/blockdev/zoned_loop.rst +++ b/Documentation/admin-guide/blockdev/zoned_loop.rst @@ -30,11 +30,10 @@ indicates the position of the write pointer of the zone. When resetting a sequential zone, its backing file size is truncated to zero. Conversely, for a zone finish operation, the backing file is truncated to the -zone size. With this, the maximum capacity of a zloop zoned block device created -can be larger configured to be larger than the storage space available on the -backing file system. Of course, for such configuration, writing more data than -the storage space available on the backing file system will result in write -errors. +zone capacity. With this, a zloop zoned block device can be configured with a +larger capacity than the storage space available on the backing file system. Of +course, for such configuration, writing more data than the storage space +available on the backing file system will result in write errors. The zoned loop block device driver implements a complete zone transition state machine. That is, zones can be empty, implicitly opened, explicitly opened, @@ -62,7 +61,7 @@ The options available for the add command can be listed by reading the /dev/zloop-control device:: $ cat /dev/zloop-control - add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u,buffered_io + add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,max_open_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u,buffered_io,zone_append=%u,ordered_zone_append,discard_write_cache remove id=%d In more details, the options that can be used with the "add" command are as @@ -71,8 +70,10 @@ follows. =================== ========================================================= id Device number (the X in /dev/zloopX). Default: automatically assigned. -capacity_mb Device total capacity in MiB. This is always rounded up - to the nearest higher multiple of the zone size. +capacity_mb Device total capacity in MiB. A smaller last zone is not + supported, so a capacity value that is not a multiple of + the zone size is rounded down to the closest multiple of + the zone size. Default: 16384 MiB (16 GiB). zone_size_mb Device zone size in MiB. Default: 256 MiB. zone_capacity_mb Device zone capacity (must always be equal to or lower @@ -80,6 +81,9 @@ zone_capacity_mb Device zone capacity (must always be equal to or lower conv_zones Total number of conventioanl zones starting from sector 0 Default: 8 +max_open_zones Maximum number of open sequential write required zones + (0 for no limit). + Default: 0 base_dir Path to the base directory where to create the directory containing the zone files of the device. Default=/var/local/zloop. @@ -104,6 +108,11 @@ ordered_zone_append Enable zloop mitigation of zone append reordering. (extents), as when enabled, this can significantly reduce the number of data extents needed to for a file data mapping. +discard_write_cache Discard all data that was not explicitly persisted using a + flush operation when the device is removed by truncating + each zone file to the size recorded during the last flush + operation. This simulates power fail events where + uncommitted data is lost. =================== ========================================================= 3) Deleting a Zoned Device |