There is a bug in the SLE command line installation tool yast which may effect SAP customers using SLES for SAP 12 SP1 (suse-sles-sap-12-sp1-byos-v20160308-hvm-ssd-x86_64, ami-4a8fb520) on AWS in conjunction with the Elastic File System (EFS).

The Architecture

A customer uses EFS for shared SAP file systems like /sapmnt or /usr/sap. An AWS system may look before the installation of the SAP software with the command df -k as follows:

nw11:~ # df -k
Filesystem    1K-blocks        Used    Available        Use% Mounted on
/dev/hda1     103078876        3286120 95477452         4% /
devtmpfs      8222944          8       8222936          1% /dev
tmpfs         12347764         0       12347764         0% /dev/shm
tmpfs         8231840          9716    8222124          1% /run
tmpfs         8231840          0       8231840          0% /sys/fs/cgroup
10.79.8.181:/ 9007199254740992 0       9007199254740992 0% /usr/sap/SI1
10.79.8.15:/  9007199254740992 0       9007199254740992 0% /sapmnt/SI1

SLES reports two file systems which have 8 Exabyte free space where as nothing is getting used.

The Bug

I have been calling yast from the command line to install an X11 environment for the upcoming SAP Netweaver installation.

yast seems to be overhelmed by the capacity of 8 Exabyte in these two additional file systems. It seems to have an integer overrun and thinks that there isn't enough disk space. It'll report the following and irrelevant message:

 You will want to continue by pushing the button [Continue anyway]. The installation will happen on the root file system and not on the two NFS mounted EFS file systems.

Then yast will come up with the following dialog:

Activate the option Do not Show This Message Again and move on with the option [Yes].

Avoiding the Problem

SUSE is processing this bug as: 991090 (yast sw_single reports "error out of diskspace" while filesystems with 8 ExaByte are mounted)

The problem can been avoided in the mean time through the three following options:

1. Install all SLES software through yast before you create the EFS file systems
2. Umount the EFS file systems before you use yast.
3. Overrule the warning. Move ahead. You will risk a full file system somewhere else