UBIFS - Revision history

Jrspruitt: Added compression type to mkfs.ubifs options

2012-10-22T07:32:19Z

Added compression type to mkfs.ubifs options

Jrspruitt: /* Creating UBI Image */

2012-10-22T07:31:05Z

‎Creating UBI Image

Tim Bird: /* fastmap support */

2012-10-12T19:37:57Z

‎fastmap support

Tim Bird at 19:31, 12 October 2012

2012-10-12T19:31:10Z

Tim Bird: /* Features */

2012-10-12T16:38:35Z

‎Features

Tim Bird: /* Features */

2012-10-12T16:35:47Z

‎Features

Tim Bird: move UBI nandsim info to UBIFS page

2012-10-12T16:35:11Z

move UBI nandsim info to UBIFS page

Tim Bird: Created page with "== Introduction == [http://www.linux-mtd.infradead.org/doc/ubifs.html UBIFS] is a filesystem that works on top of [http://elinux.org/File_Systems#UBI UBI] volumes * UBIFS pres..."

2012-10-12T16:04:35Z

Created page with "== Introduction == [http://www.linux-mtd.infradead.org/doc/ubifs.html UBIFS] is a filesystem that works on top of [http://elinux.org/File_Systems#UBI UBI] volumes * UBIFS pres..."

New page

== Introduction ==

[http://www.linux-mtd.infradead.org/doc/ubifs.html UBIFS] is a filesystem that works on top of [http://elinux.org/File_Systems#UBI UBI] volumes

* UBIFS presentation slides: [http://www.linux-mtd.infradead.org/doc/ubifs.odp ubifs.odp]

== UBIFS vs. YAFFS2 comparisons for 2.6.31.1 ==

First, see our [[Flash_Filesystem_Benchmarks]] for more recent benchmarks.

Hardware: MIPS, 403MHz CPU, 1GB Nand Flash

IOZone results: 4M, 8M & 16M file sizes in 980MB partition.

* mount time
** "1st mount" : time for mounting just after "flash_eraseall".
** "Empty" : time for mounting after "1st mount".(there's no files in partition)
** "Full" : time for mounting after creating files util the partition is full.(file size is random.)
** "Ubiattach" time for attaching 980MB partition into the ubi layer using ubiattach util.

{|border="1" cellpadding="5" cellspacing="0"
|-bgcolor="#aaaaaa"
! !! Ubiattach !! Ubifs !! Yaffs2
|-
| 1st mount || 2.59 sec || 0.17 sec || 2.25 sec
|-
| Empty || 2.57 sec || 0.11 sec || 0.03 sec
|-
| Full || 2.63 sec || 0.16 sec || 0.80 sec
|-
|}

* IOZone results

{|border="1" cellpadding="5" cellspacing="0"
|+ align="top" | UBIFS compared to YAFFS2 (file size = 4MB)
|-
! 4M !! write !! rewrite !! read !! reread !! r.read !! r.write !! b.read !! r.rewrite !! s.read !! fwrite !! frewrite !! fread !! freread
|- align="right"
| align="center" | yaffs2 || 1538 || 1527 || 296962 || 297696 || 297825 || 1521 || 296876 || 1526 || 295164 || 1536 || 1524 || 297436 || 299021
|- align="right"
| align="center" | ubifs || 19913 || 20989 || 298346 || 297631 || 299809 || 20968 || 298368 || 20181 || 299458 || 20471 || 20962 || 297371 || 297760
|- align="right" style="color:gray;" |
| align="center" style="color:black;" | ubifs/yaffs2 || style="color:green;" | 12.95 || style="color:green;" | 13.75 || 1.00 || 1.00 || 1.01 || style="color:green;" | 13.79 || 1.01 || style="color:green;" | 13.22 || 1.01 || style="color:green;" | 13.33 || style="color:green;" | 13.75 || 1.00 || 1.00
|-
|}

{|border="1" cellpadding="5" cellspacing="0"
|+ align="top" | UBIFS compared to YAFFS2 (file size = 16MB)
|-
! 16M !! write !! rewrite !! read !! reread !! r.read !! r.write !! b.read !! r.rewrite !! s.read !! fwrite !! frewrite !! fread !! freread
|- align="right"
| align="center" | yaffs2 || 1538 || 1523 || 297199 || 298525 || 298896 || 1528 || 298433 || 1525 || 298847 || 1538 || 1525 || 299661 || 300656
|- align="right"
| align="center" | ubifs || 20501 || 20656 || 298272 || 299109 || 299032 || 20521 || 298417 || 20710 || 298923 || 20448 || 20521 || 298259 || 299267
|- align="right" style="color:gray;" |
| align="center" style="color:black;" | ubifs/yaffs2 || style="color:green;" | 13.33 || style="color:green;" | 13.56
|| 1.00 || 1.00 || 1.00 || style="color:green;" | 13.43
|| 1.00 || style="color:green;" | 13.58
|| 1.00 || style="color:green;" | 13.30 || style="color:green;" | 13.46
|| 1.00 || 1.00
|-
|}

{|border="1" cellpadding="5" cellspacing="0"
|+ align="top" | UBIFS compared to YAFFS2 (file size = 32MB)
|-
! 32M !! write !! rewrite !! read !! reread !! r.read !! r.write !! b.read !! r.rewrite !! s.read !! fwrite !! frewrite !! fread !! freread
|- align="right"
| align="center" | yaffs2 || 1539 || 1525 || 296537 || 297204 || 297253 || 1527 || 297177 || 1527 || 296583 || 1531 || 1523 || 296537 || 297463
|- align="right"
| align="center" | ubifs || 20474 || 20611 || 296765 || 297490 || 297334 || 20659 || 296972 || 38416 || 297371 || 19068 || 20059 || 296618 || 296658
|- align="right" style="color:gray;" |
| align="center" style="color:black;" | ubifs/yaffs2 || style="color:green;" | 13.30 || style="color:green;" | 13.52
|| 1.00 || 1.00 || 1.00 || style="color:green;" | 13.53
|| 1.00 || style="color:green;" | 25.16
|| 1.00 || style="color:green;" | 12.45 || style="color:green;" | 13.17
|| 1.00 || 1.00
|-
|}

== Creating UBI Image ==
This is easiest to do, if you have access to the device and can run ubinfo and dmesg, otherwise you'll need to determine the volume size, Logical Erase Block size, etc by other means. UBI has some block overhead, which I found documentation inconsistent with my particular application, so your results may very. If your device is one UBI image for the entire NAND, this should be easier, and could probably be determined by just mounting a copy of the UBI image from the device if available.

To create the image from a rootfs you've built first you need to create the ubi.ini file, that describes your ubi image. Create a regular text file, ubi.ini, example contents, for more info run ubinize -h:

[ubi_rfs]
mode=ubi
image=ubifs.img
vol_id=0
vol_size=87349248
vol_type=dynamic
vol_name=ubi_rfs
vol_alignment=1
vol_flags=autoresize

Next you'll run the commands that actually build it. Here ubi.ini is the file you just created, ubifs.img is a temp file you can delete once you are done, and your_erootfs.ubi is the name of the rootfs image that will be created.

sudo /usr/sbin/mkfs.ubifs -m 2048 -e 129024 -c 677 -r /path/to/rootfs ubifs.img
sudo /usr/sbin/ubinize -o your_erootfs.ubi -p 131072 -m 2048 -s 512 -O 512 ubi.ini

To determine these and the ubi.ini file settings, use ubinfo -a and dmesg on the device if possible, which both give plenty of information about the values needed. The size and vol_name are listed under "Present volumes" when you run ubinfo -a on the device. The second half of that particular ubi device's description. While the NAND description's PEB, LEB etc are in dmesg.

mkfs.ubifs
* -m - Minimum I/O unit size.
* -e - Logical Erase Block (LEB) size.
* -c - Max LEB count. (vol_size/LEB)
* -r - Path to root filesystem.
* ubifs.img - Temporary image file.

ubinize
* -o - Output file.
* -p - Physical Erase Block (PEB) size.
* -m - Minimum I/O unit size.
* -s - Minimum I/O size for UBI headers, eg. sub-page size.
* -O - VID header offset from start of PEB.
* ubi.ini - UBI image configuration file.

@@ Line 21: / Line 21: @@
 * Good runtime performance
-=== fastmap support ===
+=== Fastmap support ===
 As of kernel version 3.7, UBI fastmap support was added to the kernel, to overcome a scalability
 issue with the time required to mount UBIFS on large flash media.
@@ Line 27: / Line 27: @@
 I specifically deals with the scalability issue described here:
 http://www.linux-mtd.infradead.org/doc/ubifs.html#L_scalability
 A description of the feature is at: http://lwn.net/Articles/517422/
 == UBIFS vs. YAFFS2 comparisons for 2.6.31.1 ==

@@ Line 20: / Line 20: @@
 * Built-in on-the-fly compression
 * Good runtime performance
 == UBIFS vs. YAFFS2 comparisons for 2.6.31.1 ==

@@ Line 19: / Line 19: @@
 * Good fault tolerance, via a number of features
 * Built-in on-the-fly compression
-* Bood performance
+* Good runtime performance
 == UBIFS vs. YAFFS2 comparisons for 2.6.31.1 ==

@@ Line 18: / Line 18: @@
 * UBI/UBIFS scales to large flash sizes better than JFFS2
 * Good fault tolerance, via a number of features
-* built-in compression
+* Built-in on-the-fly compression
+* Bood performance
 == UBIFS vs. YAFFS2 comparisons for 2.6.31.1 ==

@@ Line 140: / Line 140: @@
 * -e - Logical Erase Block (LEB) size.
 * -c - Max LEB count. (vol_size/LEB)
-* -x - Compression values lzo (default), favor_lzo, zlib, none
+* -x - Compression type: lzo (default), favor_lzo, zlib, none
 * -r - Path to root filesystem.
 * ubifs.img - Temporary image file.

@@ Line 1: / Line 1: @@
 == Introduction ==
-[http://www.linux-mtd.infradead.org/doc/ubifs.html UBIFS] is a filesystem that works on top of [http://elinux.org/File_Systems#UBI UBI] volumes
+* the UBIFS home page is at: http://www.linux-mtd.infradead.org/doc/ubifs.html
-−
 * UBIFS presentation slides: [http://www.linux-mtd.infradead.org/doc/ubifs.odp ubifs.odp]
 == UBIFS vs. YAFFS2 comparisons for 2.6.31.1 ==
-First, see our [[Flash_Filesystem_Benchmarks]] for more recent benchmarks.
+Note: see our [[Flash_Filesystem_Benchmarks]] for more recent benchmarks.
 Hardware: MIPS, 403MHz CPU, 1GB Nand Flash
@@ Line 117: / Line 133: @@
 * -O - VID header offset from start of PEB.
 * ubi.ini - UBI image configuration file.