NetApp solution for OpenStack Glance
2013-09-23 01:47 PM
I came across twitter murder torrent client ( avail on github ) that does similar job of distributing images to multiple peers, A quick test shows that it is giving good results ( Please note that we are using SSD's in RAID ) and I'm gonna use it as a last option but thought of checking with you'll if NetApp has a solution for this?
Appreciate your quick input on this
Re: NetApp solution for OpenStack Glance
2013-09-25 06:58 AM
A few considerations:
- while a BitTorrent approach has the effect of distributing I/O across a number of peers, it's predicated on creating copies across each of them. While it might be unlikely that 50G of templates would exist across all 150 nodes it would exist at least in part across a substantial percentage of them. That doesn't seem the most efficient use of host-side SSD.
- If the 150 hosts are accessing the same image (or more likely clones thereof) you may be surprised by the effect of the filers read cache (particularly if it's equipped with either FlashCache or a Flash Pool). The underlying common blocks are cached in either DRAM or Flash (dependent on filer configurations) and as a result boot / patch storms are significantly mitigated. This is one of the reasons why filers are so commonly the storage of choice for VDI deployments (which often involve simultaneous boot storms). Network utilization doesn't change per se, but you're insulated from having to descend to the disk subsystem.
- If you have your glance repository resident on an NFS export and are also mounting to /var/lib/nova/instances (with both exports residing on the same FlexVol) you could clone instead of copy upon instance creation. To be clear though this isn't explicitly provided for by Nova / Glance and would need to be externally scripted.
- Rather than contemplate the above bullet though, in Havana we've added an efficient cloning-backed instance creation capability based on boot from volume. Have a look here: https://blueprints.launchpad.net/cinder/+spec/neta
pp-cinder-nfs-image-cloning I think this might ultimately be what you're looking for.