So this m3.medium ec2 instance that packer has created to build an ami, i selected 'amazon-instance' as the type, and the ubuntu trusty source ami of type "instance-store" (as opposed to ebs, ebs-ssd, ebs-io1, and the hvm:* ones) ... it has / on xvda1 - is this ebs? How would i tell which is local ssd? m3.medium is supposed to have 1 x 4GB SSD volume, which would tend to indicate xvdb is SSD.
df
ubuntu@ip-10-61-150-2:~$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 9.9G 6.9G 2.5G 74% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
udev 1.9G 12K 1.9G 1% /dev
tmpfs 375M 204K 375M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 1.9G 0 1.9G 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/xvdb 3.9G 8.1M 3.7G 1% /mnt
fdisk
ubuntu@ip-10-61-150-2:~$ sudo fdisk -l
Disk /dev/xvda1: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders, total 20971520 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/xvda1 doesn't contain a valid partition table
Disk /dev/xvdb: 4289 MB, 4289200128 bytes
255 heads, 63 sectors/track, 521 cylinders, total 8377344 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/xvdb doesn't contain a valid partition table
And this is just really weird. How is ubuntu doing this? A 10 GB file on a filesystem reporting 5.3GB used:
ubuntu@ip-10-61-150-2:~$ ls -lh /tmp/image-1407763949
-rw-r--r-- 1 root root 10G Aug 11 14:04 /tmp/image-1407763949
ubuntu@ip-10-61-150-2:~$ df -h /tmp
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 9.9G 5.3G 4.1G 57% /