.TH VDOCALCULATESIZE 8 "2025-02-24" "Red Hat" \" -*- nroff -*-
.SH NAME
vdocalculatesize \- Calculate VDO space and memory usage
.SH SYNOPSIS
.B vdocalculatesize
.RI [ options... ]
.SH DESCRIPTION
.B vdocalculatesize
calculate VDO space and memory usage
.PP
.SH OPTIONS
.TP
.B \-\-help
Print help message and exit.
.TP
.B \-\-block-map-cache-size=\fIblocks\fP
Size of the block map cache, in 4K blocks
.TP
.B \-\-logical-size=\fIMB\fP
VDO logical size
.TP
.B \-\-physical-size=\fIMB\fP
VDO physical size
.TP
.B \-\-slab\-bits=\fIbits\fP
Set the free space allocator's slab size to 2^\fIbits\fP 4 KB blocks.
\fIbits\fP must be a value between 13 and 23 (inclusive),
corresponding to a slab size between 32 MB and 32 GB. The default
value is 19 which results in a slab size of 2 GB. This allocator
manages the space VDO uses to store user data.

The maximum number of slabs in the system is 8192, so this value
determines the maximum physical size of a VDO volume. One slab is
the minimum amount by which a VDO volume can be grown. Smaller
slabs also increase the potential for parallelism if the device
has multiple physical threads. Therefore, this value should be set
as small as possible, given the eventual maximal size of the
volume.
.TP
.B \-\-slab-size=\fIMB\fP
set slab-size directly instead of using --slab-bits. This option is
mutually exclusive with --slab-bits.
.TP
.B \-\-index-memory-size=\fIGB\fP
Specify the amount of memory, in gigabytes, to devote to the
index. Accepted options are .25, .5, .75, and all positive
integers.
.TP
.B \-\-sparse-index
Specify whether or not to use a sparse index.
.PP
.SH EXAMPLE
.nf
vdoCalculateSize --physical-size 600G --slab-bits 22 --logical-size 2T --index-memory-size 1 --block-map-cache-size 32768
.fi
.\" .SH NOTES
.SH SEE ALSO
.BR vdo (8).