Hi All please share your experience related to Data Storage size in salesforce instance is reached ? Did you increase data size from salesforce (quite expensive option) or any other option like delete/archive unused old activities etc?
It all depends. In some cases Salesforce may let you slide for a bit on your storage size limit.
Realistically, it all depends on what data you have and how you're using it.
Are you a very heavy attachment user? Can you move older attachments to a different location - or remove them completely?
Do you have single object that's taking up most of the data storage?
Do you have a bunch of records that are historical in nature and always get summarized in reports? You could collapse a bunch of data so it's just the summary data.
I believe the estimate for each salesforce record is 2kb a record. That should identify just how many records you would need to remove.
This is a situation that I've hit a couple of times.
The first was for a customer and was around loading data into a temporary table for later processing, after which it was cleaned up. As the data was short lived, we were able to exceed the limit by up to 10% at times without any ill effects. Obviously if this had been an issue it would have resulted in users not being able to save records. The way we worked around this was to persuade the customer to upgrade to Unlimited edition from Enterprise, which gives around 6x the storage limit per user license. Its not a cheap way but definitely an option.
The second was a system that was monitoring the status and performance of multiple external systems via time series data. This resulted in thousands of records being added every week and meant that it would not be possible to store more than two months worth of data. Therefore I added monthly scheduled apex that collated the previous months data into average uptime etc across the month and stored this in a different object. Another scheduled job then ran a couple of days later (in case of problems), extracted the last months time series data and emailed it to me as an attachment, then deleted it. Thus while I'd lost the absolute granularity, it was straightforward to show annual trends and performance against previous months.
+1 on summary data, if your companies process can afford to lose some detail it definitely pays to merge historical data.
If you find your self at the point where you are required to maintain large record sets but dont have the space you can always move data offsite to Heroku and the like. Use Outbound Messaging to sync the two systems and create a web service to consume the data in salesforce through visualforce pages.