Synchronizing filer system time
About synchronizing filer system time
This procedure enables you to set the timed daemon to synchronize filer system time. You can do this anytime, but if you have clusters, do it as soon as possible. After you complete this procedure, filer time is continually updated automatically.
Note
To ensure proper interaction between your storage appliance and external entities, such as Windows domain controllers, you must synchronize your appliance's time with the same external source as the domain controllers in the same domain. The lack of time synchronization might make CIFS clients unable to connect to the storage appliance.
Prerequisites
You must have available the name of at least one time server. You can get a list of NTP (Network Time Protocol) time servers, which SNTP can use, from http://www.eecis.udel.edu/~mills/ntp/servers.htm.
Synchronizing filer time
To set the timed daemon so that you can synchronize filer time, complete the following steps.
Step
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Action
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1 |
Specify, by entering the following command, the maximum discrepancy allowed before time is no longer synchronized:
options timed.max_skew nu
n is the number of units (specified by u).
u is one of the following:
- s for seconds
- m for minutes
- h for hours
The default is 30m, which stands for 30 minutes.
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2 |
Specify a protocol by entering the following command:
options timed.proto protocol
protocol is one of the following:
- rdate--For the protocol used by the rdate command
- ntp--For SNTP
The default is ntp.
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3 |
Specify a synchronization schedule by entering the following command:
options timed.sched schedule
schedule is one of the following:
- hourly--Synchronizes hourly
- multihourly--Synchronizes every six hours
- daily--Synchronizes every day at midnight
- an integer followed by m to specify an interval of minutes or h to specify an interval of hours
The default is hourly.
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4 |
Specify up to five time servers by entering the following command:
options timed.servers servers
servers is a list of the host names or IP addresses of up to five time servers, separated by commas without spaces.
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5 |
Turn on the timed daemon by entering the following command:
options timed.enable on
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6 |
If desired, turn on console logging of time changes initiated by the timed daemon by entering the following command:
options timed.log on
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Synchronizing the time with the rdate command
The rdate command synchronizes the filer date and time to an accuracy within one second of the date and time of the remote host.
How the rdate command communicates with UNIX computers
The rdate command uses the UDP protocol (typically, UDP port 37). This service is available on most UNIX computers. For detailed information about the protocol that the rdate command uses, see RFC 868.
Note
There is currently no Windows 95, Windows NT, or Windows 2000 counterpart to the rdate command. If you want to use the rdate command, you must have a UNIX workstation that supports rdate on your filer network.
Use UNIX scripts to synchronize the time periodically
To keep the filer clock accurate, regularly run the rdate command on the filer that specifies the time server. A typical scheme is to have a UNIX computer run a periodic cron job that executes the appropriate rdate command on your filer through a Remote Shell. The computer and the user (if not root) running the cron job must be in the filer /etc/hosts.equiv file on the root volume.
To synchronize the date and time with a time server using the rdate command, complete the following steps.
Step
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Action
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1 |
Check /etc/services and /etc/inetd.conf on the target computer--that is, the computer you choose as the time server--to see whether the UDP time service is supported. If the service is not supported, locate a host that supports the service before continuing to Step 2.
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2 |
Access the filer command line through the console or through a Telnet session.
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3 |
Enter the following command:
rdate host
host is the name of the time server.
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Synchronizing the time with SNTP
SNTP provides the highest degree of time synchronization accuracy. For detailed information about SNTP, see RFC 2030.
The following table describes the options used by the timed daemon. See the na_options(1) man page for a full description of the options and their possible values.
Timed option
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Function
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Default
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timed.log
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Determines whether to log time changes initiated by the timed daemon to the console.
Example
options timed.log on
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Off
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timed.max_skew
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Sets the maximum allowable discrepancy between filer time and server time.
Example
options timed.max_skew 10m
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30m
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timed.proto
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Selects whether to use the protocol used by the rdate command or the SNTP protocol (ntp).
Example
options timed.proto rdate
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ntp
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timed.sched
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Schedules when to synchronize the time with a time server.
Example
options timed.sched daily
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hourly
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timed.servers
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Specifies up to five time servers in order of contact priority.
Example
options timed.servers timeser1,
timeser2.ntap.com,10.15.46.92
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None
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To synchronize the date and time with a time server, complete the following steps.
Step
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Action
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1 |
Access the filer command line through the console or through a Telnet session.
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2 |
Set any of the timed daemon options as described in the preceding table.
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3 |
Enter the following command to enable the timed daemon:
options timed.enable on
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reserved.
Part No. 210-00472
File: admin29.htm
Last updated: 11/17/03 16:57:06