Compellent recently announced a new version of his Storage Center software (V. 5), indeed it’s not a piece of news because we are deploying it since the end of last summer but, probably for marketing reasons, they postponed the public announce. You can find here a blog post from @storagenerve that recaps the content of the announce.
After the post mentioned above I followed a little discussion on twitter about portable volumes and this article is intended to clarify some aspects about this simple, but useful, feature and something more about Compellent’s replication capabilities.
First of all replica:
Compellent has a product called Remote Instant Replay (a software feature) capable of delivering:
1. Both synchronous and asynchronous replication;
2. Unlimited Snapshots delivery (you can have history on both sites);
3. Deduplication;
4. FCP and/or IP replicas;
5. 1:1, N:1, cascading;
6. QoS;
7. Bandwidth simulation;
8. Consistency groups;
9. Portable Volumes;
10. Much more;
11. And, of course, ease of use without particular constraints (you can use all these features together on the same system)!
Yesterday I saw some misleading twitts about Portable volumes and I would like to explain better what is their real world usage.
In a traditional environment, if you want to replicate data, there are two options to begin with:
1. Install primary and secondary arrays in the same site,replicate them locally, ship one to the second site and then start the replica update process.
2. Install each system in his site and replicate data, but you need to have a large amount of time / huge bandwidth to be perform the replication priming.
In every case described above you need to spend money, time and people resources to get this job well done! Furthermore if something goes wrong and you need to restart the first time replica it can be a pain. The first sync operation consumes a huge quantity of bandwidth and time, sometime the amount time required by first sync can be measured in days or weeks!
Then Portable Volumes:
Compellent, now, has a different approach: you can still work in a traditional way but is simpler to connect these portable hard drives to the primary system, download the LUNs (large LUNs may be splitted on more disks), ship these disks (in a simple rugged bag) to the DR site, upload them for the first sync, restart the replica process!
This operation can be done for the whole systems but also for a single (or a group of) LUNs and even for a resync after a disaster, without any service interruption!
Portable volumes are simple Portable cheap 2TB USB SATA disks where you can download raw LUNs of your Comnpellent’s storage for transportation!
With Compellent you have more sophisticated replication features, if compared with traditional SANs, because you haven’t constraints, this last feature is just another way to cut your storage TCO.
BTW, Portable volumes feature is free!
You can buy PV hard drives from Compellent or buy the service from a reseller (last one is my preferred choice! 
)
ES
