[20170508]加快scp拷贝速度.txt

--//使用scp -c arcfour加快拷贝速度.仅仅做一个记录,经常忘记这个参数-c arcfour.

$ scp -c arcfour /mnt/ramdisk/book/system01.dbf oracle@192.168.100.40:/tmp
oracle@192.168.100.40's password:
system01.dbf                     100%  760MB  44.7MB/s   00:17

$ scp -c arcfour /mnt/ramdisk/book/system01.dbf oracle@192.168.100.40:/tmp
oracle@192.168.100.40's password:
system01.dbf                     100%  760MB  76.0MB/s   00:10
$ scp -c arcfour /mnt/ramdisk/book/system01.dbf oracle@192.168.100.40:/tmp
oracle@192.168.100.40's password:
system01.dbf                     100%  760MB  76.0MB/s   00:10

$ scp  /mnt/ramdisk/book/system01.dbf oracle@192.168.100.40:/tmp
oracle@192.168.100.40's password:
system01.dbf                     100%  760MB  42.2MB/s   00:18
$ scp  /mnt/ramdisk/book/system01.dbf oracle@192.168.100.40:/tmp
oracle@192.168.100.40's password:
system01.dbf                     100%  760MB  42.2MB/s   00:18

--//第一次没有缓存有点慢,需要17秒,也比后面的不加参数-c arcfour 18秒快.

# cachestats /mnt/ramdisk/book/system01.dbf
/mnt/ramdisk/book/system01.dbf           pages in cache: 194562/194562 (100.0%)  [filesize=778248.0K, pagesize=4K]

--//补充测试,在192.168.100.40删除
# rm /tmp/system01.dbf
/bin/rm: remove regular file `/tmp/system01.dbf'? y

--//重复测试:
$ scp  /mnt/ramdisk/book/system01.dbf oracle@192.168.100.40:/tmp
oracle@192.168.100.40's password:
system01.dbf                     100%  760MB  40.0MB/s   00:19

--//需要19秒,也就是正常情况下快1,2秒.而在已经缓存的情况下,速度更快.