4.9rc of yesterday
dump from B->A i.e. from a system on local ether
DUMP: DUMP: 2082890 tape blocks on 1 volume
DUMP: finished in 478 seconds, throughput 4357 KBytes/sec
^^^^^^^^^^^^^^^
and a local dump on A
DUMP: DUMP: 3560987 tape blocks on 1 volume
DUMP: finished in 3694 seconds, throughput 963 KBytes/sec
^^^^^^^^^^^^^^
why is local slower than remote?
randy
On 5 Oct, Randy Bush wrote:> 4.9rc of yesterday > > dump from B->A i.e. from a system on local ether > > DUMP: DUMP: 2082890 tape blocks on 1 volume > DUMP: finished in 478 seconds, throughput 4357 KBytes/sec > ^^^^^^^^^^^^^^^ > and a local dump on A > > DUMP: DUMP: 3560987 tape blocks on 1 volume > DUMP: finished in 3694 seconds, throughput 963 KBytes/sec > ^^^^^^^^^^^^^^ > why is local slower than remote?What are you dumping to on A? If you are dumping to a file on the same spindle, you spend a lot more time doing long seeks. Is there other I/O occuring on the same spindle as the filesystem that you are dumping on A? Could the file system on B have a small number of large files while A has a large number of small files? Has the file system on A been run in a near-full condition for a long period of time so that there are a lot of disk blocks that are poorly placed? What results do you get if you dump each file system to /dev/null on the local machine?
>> dump from B->A i.e. from a system on local ether >> >> DUMP: DUMP: 2082890 tape blocks on 1 volume >> DUMP: finished in 478 seconds, throughput 4357 KBytes/sec >> ^^^^^^^^^^^^^^^ >> and a local dump on A >> >> DUMP: DUMP: 3560987 tape blocks on 1 volume >> DUMP: finished in 3694 seconds, throughput 963 KBytes/sec >> ^^^^^^^^^^^^^^ >> why is local slower than remote? > > What are you dumping to on A?sorry. both dumping to a separate dump drive on sys A.> If you are dumping to a file on the same spindle, you spend a lot > more time doing long seeks. Is there other I/O occuring on the > same spindle as the filesystem that you are dumping on A?nope> Could the file system on B have a small number of large files while A > has a large number of small files?nope. both /usr on freebsd systems> What results do you get if you dump each file system to /dev/null > on the local machine?good question randy
Le Sun 5/10/2003, Randy Bush disait> 4.9rc of yesterday > > dump from B->A i.e. from a system on local ether > > DUMP: DUMP: 2082890 tape blocks on 1 volume > DUMP: finished in 478 seconds, throughput 4357 KBytes/sec > ^^^^^^^^^^^^^^^ > and a local dump on A > > DUMP: DUMP: 3560987 tape blocks on 1 volume > DUMP: finished in 3694 seconds, throughput 963 KBytes/sec > ^^^^^^^^^^^^^^ > why is local slower than remote?When on A are you dumping a filesystem to a device on same bus, or controller ? -- Erwan David