IPfrag Tuning - it si apcket fragmentation section. You can set arnage
of it in this option
Jumbo Frames Config also called MTU(Maximum Transmission Unit) - refers to the size (in bytes) of the largest packet that a given layer of a
communications protocol can pass onwards.
NFS Daemon tuning - you can set how many NFS daemons you want to have run in the system. On some system NFS causes NFS timeouts and chnging this value then helps. It also can improve NFS performance.
Read ahead disk tuning - with this option you can increase for better
performance size of cache. In some cases it is rquierd to decrese it for
better compatiblity.
iSCSI daemon option - in this option you can set values of iSCSI target:
a) MaxRecvDataSegmentLength - Sets the maximum data segment length that can be received. This value should be set to multiples of PAGE_SIZE.
Currently the maximum supported value is 64 * PAGE_SIZE, e.g. 262144 if
PAGE_SIZE is 4kB. Configuring too large values may lead to problems
allocating sufficient memory, which in turn may lead to SCSI commands
timing out at the initiator host. The default value is 8192.
b) MaxBurstLength - Sets the maximum amount of either unsolicited or
solicited data the initiator may send in a single burst. Any amount of
data exceeding this value must be explicitly solicited by the target.
This value should be set to multiples of PAGE_SIZE. Configuring too
large values may lead to problems allocating sufficient memory, which in
turn may lead to SCSI commands timing out at the initiator host. The
default value is 262144.
c) MaxXmitDataSegmentLength - Sets the maximum data segment length that can be sent. This value actually used is the minimum of MaxXmitDataSegmentLength and the MaxRecvDataSegmentLength announced by the initiator. It should be set to multiples of PAGE_SIZE. Currently the maximum supported value is 64 * PAGE_SIZE, e.g. 262144 if PAGE_SIZE is 4kB. Configuring too large values may lead to problems allocating sufficient memory, which in turn may lead to SCSI commands timing out at the initiator host. The default value is 8192.
d) DataDigest - If set to "CRC32C" and the initiator is
configured accordingly, the integrity of an iSCSI PDU's data segment
will be protected by a CRC32C checksum. The default is "None". Note that
data digests are not supported during discovery sessions.
e) MaxOutstandingR2T - Controls the maximum number of data
transfers the target may request at once, each of up to MaxBurstLength
bytes. The default is 1.
f) InitialR2T - If set to "Yes" (default), the initiator has to
wait for the target to solicit SCSI data before sending it. Setting it
to "No" allows the initiator to send a burst of FirstBurstLength bytes unsolicited right after and/or (depending on the setting of ImmediateData together with the command. Thus setting it to "No" may
improve performance.
g) ImmediateData - This allows the initiator to append
unsolicited data to a command. To achieve better performance, this
should be set to "Yes". The default is "No".
h) DataPDUInOrder - It tells initiator if data has to be sent
in order. Defualt is "Yes", which is also recommended.
i) DataSequencerInOrder - It tells initiator if data has to be
sent in order. Defualt is "Yes", which is also recommended.
j) HeaderDigest - If set to "CRC32C" and the initiator is
configured accordingly, the integrity of an iSCSI PDU's header segments
will be protected by a CRC32C checksum. The default is "None". Note that header digests are not supported during discovery sessions.
k) Wthreads - The iSCSI target employs several threads to perform the
actual block I/O to the device. Depending on your hardware and your
(expected) workload, the number of these threads may be carefully
adjusted. The default value of 8 should be sufficient for most purposes.
