Hi Champaka
So as a quick guide, (the KB articles will give you a better idea)
For each aggregate configured in the way you are talking…
Things to consider…
Raw space then is 11x300Gb Drives – lets say 3.3Tb give or a take…
Things to consider
1. Disk right sizing – those 300Gb drives are not 300Gb they are actually 272Gb once they are right sized (leaving 2992gb)
2. 2 parity drives will then remove another 544gb (2448gb)
3. Wafl and OS overhead, lets take around another 10% for that, so about 250Gb (2198Gb)
So around 2.1tb is your usable space…
You then have to consider things like snapshot reserve etc so if you applied to each volume a “standard” (as snap reserve needs to be set to whatever is appropriate for your retention requirements) reserve of say 20% that would remove around 440gb so we are down to 1558gb or data space that can be presented to users and apps….
A really good guide as a starting point, especially in smaller environments is if you half the raw capacity, that will be about the usable space… if you look at the above, that pretty much applies here…
Don’t forget to have each controller with a list one spare disk, per disk type…so if you have SAS and SATA drives for example on a controller there should be at least one of each type as a spare…
Although this may sound a lot of “lost” disk…you have to look at what you are getting…one you start to use snapshots, thin provisioning, clones etc….you’ll soon find yourself over provisioning! And having much more presented capacity than you have real disk….
Check the KB articles as suggested and you’ll find more detail on the above…but those rough guidelines should stand you in good stead.
