Enterprise Vault Sizing Tool output - is this right?
Hello
This is for those of you with access to the Sizing Estimator for Enterprise Vault (I've used the latest version)
I have run the mailbox analyzer tool and exported the results to an XML file. This XML file is imported into Excel, and this "fabulous" worksheet that will give us some information about how much is in the backlog (to archive), and how much will be archived in the three years to come.
So far so good, but I think these numbers are strange (see attached image) and I find it extremely strange that
- The backlog size is smaller than the 1st year (and 2nd and 3rd year, but that is obviously because we expect data in Exchange to grow from Year 1)
- Index size is 3/4 of the vault store size.
I have used default values more or less.
Someone else experienced strange output, or could it be something I am missing out completely here?
Any (useful) help is much appreciated
Andy Joyce actually taught me this one, when I had the same question......
Indexes are based on a per user archive not a per item.
For example, if you have 2 users that have a 1 MB email, each user index will be 130kb (roughly) for a total of 260kb of total index against a 1 MB item. (See your message attachment SIS ratio)
So total storage is
800KB for the actual email (at 80% compression)
260 KB for the index of the 2 users
So it does look like the indexes are larger than 13%, more like 26% of the original item, but you have to take into account each user's individual index.
The use of SIS allows you to reduce the amount of storage required for the original item, but does not change the amount of space required for the use index.
The advantage of having a per user archive is that in the event of a corruption or disk failure, you only need to rebuild some indexes instead of one big index (which could take an extended period of time). Smaller indexes are less prone to corruption also.
You also have some monster size messages with lots of attachments to index
758KB for average message size is huge.
So be aware that your performance metrics wont be anywhere close. EV performance metrics are based on average message size of 70kb. For each doubling of the size, throughput drops by 1/3. Therefore the performance guide states 8 core CPU is roughly 50,000 items per hour at 70KB.
Without having to relearn calculus for the formula to figure out your expected performance, keep in mind it may look like EV is slow if you look at message throughput per hour.