As I said, we do use NTP to keep our machines in synchronization, every
hour. However, there's no time client that will keep everything aligned
up to the nanosecond level, which is what ext4 timestamps are in.
Besides, any amount of network lag is going to introduce small errors in
this anyway. The only temporary solution I can think of is to force the
clock on the NFS server to be ~1 second behind all of the clients, so
timestamps will never appear to be in the future. Not a clean
workaround, but it appears there's no other stopgap solution.
On 01/12/2011 09:58 PM, Bob Friesenhahn wrote:
On Wed, 12 Jan 2011, Eric Reischer wrote:
I recently upgraded our NFS fileserver to an ext4 filesystem, and
since then we've been having clock skew warnings from make (3.81).
Because the ext3 filesystem that was previously running on the NFS
server didn't support high-precision timestamps, we didn't have clock
skew warnings because an hourly cron job kept the clocks in
relatively close sync. However, since ext4 does support sub-second
timestamps, we're getting warnings about clock skews on the order of
a few milliseconds. I tried adding our target objects
Usually the solution to this is to install and run ntp (Network Time
Protocol, as offered by 'xntp') on the machines on your network. This
seems to be quite effective on real hardware, and sometimes less
effective in virtual machines (e.g. VMWare or Virtualbox) which can
only emulate the hardware clock. I am not aware of a more effective
method than using ntp.
Bob
