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On September 25, 2015 3:27:20 AM EDT, Felix Miata
Greg Freemyer composed on 2015-09-23 15:38 (UTC-0400):
David C. Rankin wrote:
Felix Miata wrote:
This isn't on a filesystem with a small blocksize, is it?
Nope, this was a fresh install on one of the space-wasting 4k new-fangled 7200 rpm platters :-)
Uhh....Space Wasting?
On a TW/KDE installation, search for *.png in /usr/ tree produced 15,766 hits.
A tiny sample, /usr/share/emoticons/Breeze, has 29,027 bytes in 35 files. Moving those 35 files off a filesystem with 1k blocksize frees 43,008 bytes, 42 1k blocks, a wasted space ratio of 32.5%. Moving them onto a filesystem with 4k blocksize consumes 36 4k blocks, 147,456 bytes, a wasted space ratio of 80.3%.
On same installation, /usr/share/kf5/locale/countries has 241 directories and 655 bytes in 20 files. Each of those 241 directories contains two small files, about half of which are less than 512 bytes, and few of which are more than 1024 bytes. du -s says this group 743 blocks on a 1k block filesystem, so 246,784 bytes. Moving them off the 1k block filesystem freed 760,832 bytes, onto a 4k block filesystem, using 734 4k blocks, 3,006,464 bytes, a 3.95:1 ratio between consumption on the two filesystems.
IIRC, last I compared freespace rsyncing a root partition on a 4k block 4.8G filesystem onto a 1k block 4.8G filesystem saved somewhere in the neighborhood of 15% of freespace difference between the two.
Based on these observations, it's easy to see at least potential loss of space using 4k instead of smaller blocksize is a lot bigger than inconsequential.
It's a seriously good thing storage densities continue to rise, and unit cost continues downward, but they don't necessarily interplay nicely with smaller sizing paradigms WRT backup strategies, or size limitations of backup media.
Linux went to a 4KB page for almost all filesystems over a decade ago.
That's where defaults went. Not everyone uses defaults. I have far more filesystems using 1k blocks than those using larger. I use larger only where A/V media and iso files go if on 512b/s disks, which I have far more of than 4k/s disks.
So, yes, space wasting!
Just one comment "However, by modifying the length of the data field through the implementation of Advanced Format using 4096-byte sectors, hard disk drive manufacturers could increase the efficiency of the data surface area by five to thirteen percent while increasing the strength of the ECC." So, sticking with 512 byte sectors effectively wastes 5 to 13% of the potential storage on the platter due to inefficient headers/footers. You should buy what works best for you, but I suspect over 95% of users go with the default 4kb filesystem page. Greg -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org