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About the Fibre Transport chunk size
See
"Settings > Network > Fibre Transport"
See
"Supported Fibre Channel port configurations for the NetBackup 5220 and
5230 appliances"
on page 37.
See
"Supported Fibre Channel port configurations for the NetBackup 53xx
appliances"
on page 47.
See
"Supported Fibre Channel port configuration for the NetBackup 5240 appliances"
on page 43.
See
"About the Fibre Transport chunk size"
The chunk size specifies the amount of data that is buffered before transmission
over Fibre Transport (FT). It is an advanced setting on the sender side for optimized
duplication and replication to other NetBackup appliances over FT.
By default, the chunk size is not set or used. The chunk size setting is not required
for optimized duplication and replication over FT. It is highly dependent on user
deployment and network status. If you find it necessary to improve backup
performance, you can adjust the chunk size as needed to determine a proper value
for your environment and the current network status.
Typically, the sender on the initiating appliance receives a block of data and starts
the transmission regardless of its size. After this data block is transmitted, the sender
waits for a confirmation from the receiver (or target appliance) before it transmits
the next block. The transmission continues if the appliance receives confirmations
without interruption. If the network latency is high, confirmation time also increases.
By setting the chunk size, you determine that data blocks must be delivered by
using chunks of the specified size. In a single transmission session, if the sender
receives a block of data that is greater than the specified chunk size, it fragments
the data into chunks for transmission. The remaining data from the fragmentation
is allocated to the next chunk. If a data block is smaller than the specified chunk
size, the sender adds it into the buffer to link it together with data from the preceding
or the following block. Data block linking continues until the buffered data has
reached the chunk size, and then the appliance transmits the chunk. After
transmitting, the sender waits for a confirmation from the receiver before it sends
out the next chunk. If the session closes, the remaining data is transmitted.
A data block over FT is typically 128 KB or smaller. Setting the chunk size to a
value equal to or greater than 128 KB allows the appliance to link together small
data blocks into big chunks. Therefore, fewer confirmations are needed. The result
may improve the transmission efficiency when the network latency is high. The data
block linking also reduces the overhead that is generated with the data.
Configuring Fibre Transport on the appliance
Configuring Fibre Transport to other NetBackup appliances
on page 59.
on page 70.
70
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