Azure quirks

[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.

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