Project and Share Properties
object type" and check for a higher rate of sustained DDT operations (Data Duplication Table
operations) as compared to ZFS operations. If this is happening, more I/O is for serving the
deduplication table rather than file I/O.
To use deduplication with encryption, keep in mind that only AES with the CCM mode
encryption is compatible with deduplication. For more information, see “Managing Encryption
Keys” on page 582.
Data compression
The data compression property controls whether data is compressed before being written
to disk. Shares can optionally compress data before writing to the storage pool. This allows
for much greater storage utilization at the expense of increased CPU utilization. By default,
no compression is done. If the compression does not yield a minimum space savings, it is
not committed to disk to avoid unnecessary decompression when reading back the data.
Before choosing a compression algorithm, it is recommended that you perform any necessary
performance tests and measure the achieved compression ratio.
BUI value CLI value Description
Off off No compression is done
LZJB (Fastest) lzjb A simple run-length encoding that
only works for sufficiently simple
inputs, but doesn't consume much
CPU.
GZIP-2 (Fast) gzip-2 A lightweight version of the gzip
compression algorithm.
GZIP (Default) gzip The standard gzip compression
algorithm.
GZIP-9 (Best Compression) gzip-9 Highest achievable compression
using gzip. This consumes a
significant amount of CPU and can
often yield only marginal gains.
Checksum
The checksum property controls the checksum used for data blocks. On the appliance, all data
is checksummed on disk, and in such a way to avoid traditional pitfalls (phantom reads and
write in particular). This allows the system to detect invalid data returned from the devices.
The default checksum (fletcher4) is sufficient for normal operation, but users can increase the
checksum strength at the expense of additional CPU load. Metadata is always checksummed
using the same algorithm, so this only affects user data (files or LUN blocks).
Shares and Projects 367
To Next Page
Loading...
Need help?
General
