diff --git a/man/lvmthin.7.in b/man/lvmthin.7.in index 55b156229..5a4ee875f 100644 --- a/man/lvmthin.7.in +++ b/man/lvmthin.7.in @@ -23,10 +23,10 @@ that will hold blocks for thin LVs, and a metadata LV that will hold metadata. The metadata tracks which data blocks belong to each thin LV. Snapshots of thin LVs are efficient because the data blocks common to a -thin LV and its snapshot are shared. Snapshots may be taken of thin LVs -or of other thin snapshots. Blocks common to recursive snapshots are also -shared in the thin pool. There is no limit to or degradation from -sequences of snapshots. +thin LV and any of its snapshots are shared. Snapshots may be taken of +thin LVs or of other thin snapshots. Blocks common to recursive snapshots +are also shared in the thin pool. There is no limit to or degradation +from sequences of snapshots. As thin LVs or snapshot LVs are written to, they consume data blocks in the thin pool. As free data blocks in the pool decrease, more free blocks @@ -620,6 +620,9 @@ pool0 vg twi-a-tz-- 10.00g 47.01 21.03 thin1 vg Vwi-aotz-- 100.00g pool0 2.70 .fi +The "Discard" section covers an option for automatically freeing data +space in a thin pool. + .SS Automatically extend thin pool LV @@ -691,7 +694,7 @@ extended. (Disabling dmeventd is not recommended.) writes to thin LVs in the pool. (This can be addressed by tuning the thin_pool_autoextend_threshold and thin_pool_autoextend_percent.) -4. The VG does have enough free blocks to extend the thin pool. +4. The VG does not have enough free blocks to extend the thin pool. The response to data space exhaustion is to extend the thin pool. This is described in the section "Manually manage free data space of thin pool @@ -768,8 +771,10 @@ controls the default zeroing mode used when creating a thin pool. \& -The discard behavior of a thin pool LV determines how discard requests -are handled. Possible discard behaviors: +The discard behavior of a thin pool LV determines how discard requests are +handled. Enabling discard under a file system may adversely affect the +file system performance (see the section on fstrim for an alternative.) +Possible discard behaviors: ignore: Ignore any discards that are received. @@ -933,7 +938,7 @@ and combines the two into a thin pool LV. lvcreate -L LargeSize --thinpool VG/ThinPoolLV Example -# lvcreate -l1 --thinpool vg/pool0 +# lvcreate -L8M --thinpool vg/pool0 # lvs vg/pool0 LV VG Attr LSize Pool Origin Data%