UBI, no sub-pages support
Dear all,
i am running UBI/UBIFS on a TI AM1808 / OPAM-L cpu, MT29F1G08 NAND and kernel 3.5.1.
MT29F1G08 has 128KB pages, and 2048B PEB's.
After first attempt to create UBI/UBIFS image using 512B sub-pages, i had several UBI errors, so i realized sub-pages are not supported in the OMAP-L driver at this kernel version (seems to start to be supported form 3.10.x).
So i prepare the image from buildroot without subpage now, with these settings:
[ ] jffs2 root filesystem
[*] ubifs root filesystem
(0x1f000) UBI logical erase block size
(0x800) UBI minimum I/O size
(1024) Maximum LEB count
ubifs runtime compression (gzip) --->
Compression method (no compression) --->
[*] Embed into an UBI image
(0x20000) UBI physical erase block size
(0) UBI sub-page size
buildroot/output/host/usr/sbin/mkfs.ubifs --space-fixup -d buildroot/output/target -e 0x1f000 -c 1024 -m 0x800 -x zlib -o buildroot/output/images/rootfs.ubifs
buildroot/output/host/usr/sbin/ubinize -o buildroot/output/images/rootfs.ubi -m 0x800 -p 0x20000 ubinize.cfg
I executed both mtd-utils "runtest.sh" and integck, and had no issues. Could you maybe confirm this settings are correct and i am not going trough issues using the fs ?
Another question is: is there a UBI performance loss using pages as minimal I/O (no subpages) or i can consider it insignificant ?
Many Thanks
Angelo Dureghello
Quoted 2 lines · Angelo Dureghello
Another question is: is there a UBI performance loss using pages as minimal I/O (no subpages) or i can consider it insignificant ?
I can only comment on this question - you should not lose performance, but you'll have more NAND flash space consumed by UBI for its own purposes, comparing to what you'd have if you had sub-pages.
IOW, sub-pages are mostly lessening the UBI space overhead.
The MTD web page has a section about the space overhead with some more information.
Signature · 2 lines
Best Regards, Artem Bityutskiy