Bugzilla to JIRA migration: definitive approach for mapping entire bugzilla db->product->component hierachy to JIRA?

Our organisation is now using JIRA and I'm looking to migrate a bugzilla database of about 1500 entries into it.

I'm aware that JIRA has projects but not of divisions within this.

My firm preference is to have one JIRA project for this bugzilla database and the bugzilla products then components all contained within this. This keeps the database self contained and doesn't expose (and therefore overcrowd) the top level project list in JIRA with my department specific bugzilla products.

Given that there is not a straight one-to-one mapping of the hierachy in bugzilla with that in JIRA, I would consider custom fields to implement the bugzilla product and component levels in JIRA and build a custom JIRA webpage with a form that would auto-present 开发者_开发知识库the correct components once a product is selected (much as is the case in the bugzilla). I'm aware that JIRA is highly customisable with APIs but I don't know the detail yet - this is where I would need advice.

I've attempted some research but this is inconclusive: http://forums.atlassian.com/message.jspa?messageID=257299050

So in summary:

1. Is custom fields the definitive/accepted way to represent bugzilla products and their components in JIRA. Any disadvantages?
2. If so, are there examples, suggest as to how to implement this - and the form that auto-suggests the components, once a product is selected.
3. If not, then what would be the alternative to using custom fields?

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You could save yourself a lot of work by equating the Bugzilla product to JIRA projects, so that you could map the components directly from Bugzilla to JIRA. You'd then get the auto-suggestion of the component list for each project for free rather than having to do a bunch of customization.

I've used JIRA in five different organizations and have always mapped each team or division to one or more JIRA projects. Each JIRA project can then have its own versions and release dates as well as components, which seems like a natural match to Bugzilla products.