To maintain compatibility across brands of disks, Data ONTAP rounds down ("right-sizes") the amount of space available for user data.
Because of right-sizing, informational commands such as sysconfig show a lower number for available space than the disk's rated capacity (you use rated capacity if you specify disk size when creating an aggregate). The available disk space is rounded down as shown in the following table.
The capacity numbers in this table do not take into account the 10 percent of disk space that Data ONTAP reserves for its own use.
| Disk size | Right-sized capacity | Available blocks |
|---|---|---|
| FC disks | ||
| 18 GB | 17 GB | 34,816,000 |
| 35 GB | 34 GB | 69,632,000 |
| 36 GB | 34.5 GB | 70,656,000 |
| 72 GB | 68 GB | 139,264,000 |
| 144 GB | 136 GB | 278,528,000 |
| 300 GB | 272 GB | 557,056,000 |
| ATA disks—FC connected | ||
| 250 GB | 212 GB | 432,901,760 |
| 320 GB | 274 GB | 561,971,200 |
| 500 GB | 423 GB | 866,531,584 |
| 750 GB | 635 GB | 1,301,618,176 |
| 1 TB | 847 GB | 1,735,794,176 |
| SAS disks—SAS connected | ||
| 144 GB | 136 GB | 278,528,000 |
| 300 GB | 272 GB | 557,056,000 |
| SATA disks—SAS connected | ||
| 250 GB | 212 GB | 432,901,760 |
| 500 GB | 423 GB | 866,531,584 |
| 750 GB | 635 GB | 1,301,618,176 |