D-Link xStack Storage DSN-4000 Series, Software User'S Manual

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98 Chapter 6 System Administration
Table 6-4. Advanced System Settings
Advanced Setting Description
Remote System Time Date and time of the storage system, adjusted for its local time zone.
NTP (Time Server) IP Address Enter the IP address of the NTP Time Server to allow the storage system to
synchronize its date and time with an external time server. The Default IP
address is 0.0.0.0, which indicates that no time server synchronization will be
performed.
iSCSI Port Number Specifies the TCP port number used for the iSCSI communication. The default
value for the iSCSI protocol is 3260 and should not be changed.
TCP/IP – Time to Live Specifies the Time To Live value set in the header of outgoing IP packets. This
value determines the maximum number of seconds an IP packet can live in the
network without reaching its destination. This limits the number of hops an IP
packet can pass through before being discarded. The allowable range is 60 to
255 seconds. The default is 64 seconds.
TCP/IP – Maximum IP Segmentation Specifies the largest amount of data, in bytes, that TCP is willing to send in a
single segment. For best performance, this value should be set small enough to
avoid IP fragmentation, which can lead to excessive retransmissions if there is
packet loss. The allowable range is 512 to 65535 bytes. Default is 8960 bytes.
TCP/IP – Window Scale For efficient use of high bandwidth networks, a larger TCP window size can be
used. This option increases the maximum window size from 65,535 bytes to 1
Gigabyte. Scaling up to larger window sizes is a part of what is necessary for TCP
Tuning. This option is used only during the TCP 3-way handshake. The window
scale value represents the number of bits to left-shift the 16-bit window size field.
The window scale value can be set from 0 (no shift) to 14. Default is 0.
TCP/IP – Timestamp
Causes the receiving computer to send a time-stamp reply back to the originating
computer. Systems can use time-stamp requests and replies to measure the
transmission speed of datagrams on a network. Choices are:
Enabled = TCP/IP timestamp is enabled.
Disabled = TCP/IP timestamp is disabled. ( default )
TCP/IP – PMTU
Determines whether the storage system automatically adapts its packet size.
Choices are:
Enabled = automatically adapts its packet size. ( default )
Disabled = keeps its default packet size (576 bytes), even if it receives an
ICMP request to change its packet size. This can render some remote
systems unreachable, because if intermediate systems on the path to the
remote system cannot support the default packet size, the storage system
ignores their requests to make the packets smaller.
TCP/IP – Reset Upper Layer Counter
Determines whether the TCP/IP upper layer counters can be reset. Resetting the
counters simplifies the ability to look at the counters for an accurate percentage of
packets sent or received. Choices are:
Enabled = upper layer counters can be reset.
Disabled = upper layer counters cannot be reset. ( default )
iSNS Enabled
Indicates whether iSNS is enabled. Choices are:
Enabled = iSNS is enabled and will register clients automatically
Disabled = iSNS is not enabled. ( default )
iSNS Server IP Address
Enter the IP address of the iSNS server. Default is 0.0.0.0.
iSNS Server Subnet Mask
Enter the subnet mask of the iSNS server. Default is 255.255.255.0.
iSNS Server Port
Enter the port of the iSNS server. Default is 0.
Default Block Size
Specifies the default block size that should be used for all newly created volumes.
Choices are:
512 bytes ( default )
4096 bytes (allows volume sizes up to 16TB with 32-bit operating systems)