On 08/25/2019 07:36 AM, Pascal Hambourg wrote:
Le 25/08/2019 à 13:20, Richard Owlett a écrit :How do I search for answer to my inadequately phrased question below. 1. I assume that sector size is a _TERM_ reserved for something fixed when the disk is manufactured.With modern disks, there are two sector sizes : - the physical sector size, either 512 or 4096 bytes. - the logical sector size, usually 512 but sometimes 4096 bytes.
Consistent with my poorly expressed mental image.
This is of course different from the filesystem block size which is a multiple of the logical sector size, and should be a multiple of the physical sector size for optimal performance.2. What is the proper search term to use for something whose dimensions would be "megabytes/inode"? {I'll use "blob" for now }This is just a ratio without any actual object associated. It should be chosen close to the estimated average file size to avoid running out of inodes when there are still plenty of free blocks or the other way around. The file size to account for is the "real" on-disk size, including the unused space in the last block. In short, it is the size rounded to the next block size boundary.
Would "logical sector size" be equivalent to "blob"?I thinking in terms of "Will all "sectors" associated with a specific inode be physically adjacent?"
3. The references I skimmed were focused pretty much on "disk full" meaning either running out of "inodes" or "physical bytes on disk". the question: How find discussion of blob size v file fragmentation [cf head seeks in spinning rust] blob size v wear problems on SSD [unclear how that's handled now] blob size v parameters such as bs when using dd [lousy example]AFAIK, the inode ratio does not matter for these topics. The disk sector sizes and filesystem block sizes matter more.
Is that different than saying {(blob size)==(block size)}?
Or am I totally confused?
Thank you.