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Sorry in advance if this is the wrong place for this kind of question.

I'm porting some of my EC2 application's start scripts to the 11.10 ami-21f53948 AMI, from a similar 9.10 (ami-6832d801).

One step of the process is to raid together the 4 ephemeral drives that come with a c1.xlarge. In the the previous AMI these could be found at /dev/sd[b-e]. These devices appear to be absent in the new AMI.

It seems an instance using the new AMI believes they should be there:

$ curl 'http://169.254.169.254/latest/meta-data/block-device-mapping/' && echo
ami
ephemeral0
ephemeral1
ephemeral2
ephemeral3
root
$ curl 'http://169.254.169.254/latest/meta-data/block-device-mapping/ephemeral0' && echo
sdb
$ curl 'http://169.254.169.254/latest/meta-data/block-device-mapping/ephemeral1' && echo
sdc
$ curl 'http://169.254.169.254/latest/meta-data/block-device-mapping/ephemeral2' && echo
sdd
$ curl 'http://169.254.169.254/latest/meta-data/block-device-mapping/ephemeral3' && echo
sde

Does anyone have any light to shed on what I can do here? Perhaps they are available under different names (despite the block device mapping) or maybe I can create the needed device files? Any help is appreciated.

While it's not clear exactly how, this issue report may be related. Much like the goggles, passing the block device mapping arguments to ec2-start-instances (as one post suggested) did nothing.

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1 Answer 1

up vote 0 down vote accepted

The block device mapping is wrong. The ephemeral drives can be found at /dev/xvd[b-e], following the virtualized block device naming scheme.

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