Could you please give me the detailed parameter of the 'IPfrag tuning', 'Jumbo Frames Config', 'NFS Daemon tuning' , 'Read ahead disk tuning' and 'iSCSI daemon option ' in the 'Tuning options'.
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.
沒有留言:
張貼留言