Azure本地磁盘 - 它去了哪里？ （Linux VM）

Question

The Azure VM table...

https://www.windowsazure.com/en-us/pricing/details/#header-2

...says that, for example, a Medium Instance comes with 490GB of local storage. So I was expecting the usual 30GB Azure BLOB OS disk, and then a 490GB /mnt/resource.

But no:

$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
                       28G  1.7G   25G   7% /
tmpfs                 1.7G     0  1.7G   0% /dev/shm
/dev/sda1             485M   68M  392M  15% /boot
/dev/sdb1             133G  188M  126G   1% /mnt/resource

That's on the CentOS image, but it's the same for other images.

Am i missing something? I don't see the space in a volume group or anything, and there are no sd* devices that aren't mounted.

Answer 1

Neil Mackenzie's answer in the comments appears to be correct

All Windows Azure IaaS VMs come with two disks - an OS disk backed by a VHD persisted in Windows Azure Blob storage and a temp disk physically attached to the hosting server. This temp disk is truly ephemeral and any contents on it will be lost if the VM is deallocated (shutdown on the portal or API) or moved for server healing. For Linux VMs this temporary disk /dev/sdb.

I found this link to corroborate: http://blogs.msdn.com/b/wats/archive/2013/12/07/understanding-the-temporary-drive-on-windows-azure-virtual-machines.aspx