[root@foo html]# time cp src31/ leiyp -a real 3m33.343s user 0m0.447s sys 0m5.144s [root@foo html]# time cp src31/ lep -a real 0m14.093s user 0m0.320s sys 0m4.000s [root@foo html]# time cp src31/ les -a real 0m7.885s user 0m0.339s sys 0m4.237s [root@foo html]# time cp src31/ lems -a real 0m9.902s user 0m0.324s sys 0m4.320s [root@foo html]# du -sh src31/ 517M src31/
First copy took ages… and then things go fast…
Well the disk don’t behave like on a normal system
[root@foo ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 29G 9.0G 19G 34% / tmpfs 14G 0 14G 0% /dev/shm /dev/md127 79G 21G 55G 27% /var/lib/mysql /dev/sdc1 99G 66G 28G 71% /var/www /dev/sdb1 197G 60M 187G 1% /mnt/resource [root@foo ~]# hdparm -tT /dev/sda1 /dev/sda1: Timing cached reads: 12396 MB in 1.99 seconds = 6229.11 MB/sec Timing buffered disk reads: 38 MB in 3.06 seconds = 12.41 MB/sec [root@foo ~]# hdparm -tT /dev/sdc1 /dev/sdc1: Timing cached reads: 12002 MB in 1.98 seconds = 6046.37 MB/sec Timing buffered disk reads: 8 MB in 3.90 seconds = 2.05 MB/sec [root@foo ~]# hdparm -tT /dev/md127 /dev/md127: Timing cached reads: 11688 MB in 1.99 seconds = 5868.12 MB/sec Timing buffered disk reads: 170 MB in 3.02 seconds = 56.20 MB/sec
Also system is not idle is on production but compared to a consumer SATA Seagate Barracuda 7200.14 (ST2000DM001-1ER164) I get this.
hdparm -tT /dev/sda /dev/sda: Timing cached reads: 37552 MB in 2.00 seconds = 18802.96 MB/sec Timing buffered disk reads: 586 MB in 3.00 seconds = 195.07 MB/sec
Also a production machine, but not that busy and sitting on my desktop, bummer
A better comparison, a linode 8GB instance also a production one and busy:
root@bar:~# hdparm -tT /dev/sda /dev/sda: Timing cached reads: 14546 MB in 2.00 seconds = 7280.14 MB/sec Timing buffered disk reads: 1940 MB in 3.00 seconds = 646.64 MB/sec root@bar:~# hdparm -tT /dev/sdd /dev/sdd: Timing cached reads: 14244 MB in 2.00 seconds = 7131.55 MB/sec Timing buffered disk reads: 1074 MB in 3.01 seconds = 356.59 MB/sec
Also to disclose this is not a slow entry VM is a Standard D12 v1 (4 Cores, 28 GB memory) of Intel(R) Xeon(R) CPU E5-2660 0 @ 2.20GHz.
