I've been seeing more and more android builds switching to ext4 (iDroidProject included) journalling system. Does our 2.6.32 kernel support ext4, and if not is there a way to include it in the kernel build?
Reason I'm asking is from what I'm understanding the ext4 journalling system could solve alot of issues in terms of data corruption, and slowness?
I see that the Gingerbread devices have this by default, but from what I understand, the kernel is the one that needs to support this, not the OS.
I would like to hear your thoughts on this, as I'm completely unfamilar with this area. lol
Krazy-Killa said:
I've been seeing more and more android builds switching to ext4 (iDroidProject included) journalling system. Does our 2.6.32 kernel support ext4, and if not is there a way to include it in the kernel build?
Reason I'm asking is from what I'm understanding the ext4 journalling system could solve alot of issues in terms of data corruption, and slowness?
I see that the Gingerbread devices have this by default, but from what I understand, the kernel is the one that needs to support this, not the OS.
I would like to hear your thoughts on this, as I'm completely unfamilar with this area. lol
Click to expand...
Click to collapse
Same here, would like to know,
Prowess said:
Same here, would like to know,
Click to expand...
Click to collapse
Ext4 can be added in our kernel, I initially thought that this filesystem is for external memory and not applicable for NAND but if they are doing it with IDROID then I think we need to edit our init to support this + support for the kernel. Is there full support for ext4 on NAND? Can you give us a link?
ext4 has a high number of writing cycle so the nand will be destroyed very fast.
For the same reason it isn't enabled for sd.
l1q1d said:
ext4 has a high number of writing cycle so the nand will be destroyed very fast.
For the same reason it isn't enabled for sd.
Click to expand...
Click to collapse
That part may be true, and if that were the case. Then the benefit must outway the cost, especially if its being used for the iDroid for the older iPhone and 3G models which have been around for probably as long as our Kaisers.
Plus hasn't flash memory evolved even in older devices like ours to handle over a billion (probably exagerating on this) writes in its lifetime?
Hell USB flash drives are now used as removable RAM sticks on modern computers and laptops, plus used in bootable media like Linux/Ubuntu.
And also as you stated ext4 uses A LOT of write cycles right? Then why are the newer Androids using ext4 if it'll destroy the NAND very quickly?
Sent from my AT&T Tilt using XDA App
I still wouldn't push it. Most of us have bad blocks on our NAND already.
aceoyame said:
I still wouldn't push it. Most of us have bad blocks on our NAND already.
Click to expand...
Click to collapse
Well, hate to say it but from what I'm seeing here is almost exactly like what happened when the NTFS system was released for NT4. A lot of people complained that it would destroy older drives, with its higher write and read cycles. Granted this is completely different than hard drives, but too me feels the like the same situation almost 12 yrs ago.
I'm just saying what's the harm of putting it in the kernel and warning people of the potential risks involved (as always lol).
Hell isn't having Android on the Kaiser a risk anyways?
Sent from my AT&T Tilt using XDA App
Krazy-Killa said:
Well, hate to say it but from what I'm seeing here is almost exactly like what happened when the NTFS system was released for NT4. A lot of people complained that it would destroy older drives, with its higher write and read cycles. Granted this is completely different than hard drives, but too me feels the like the same situation almost 12 yrs ago.
I'm just saying what's the harm of putting it in the kernel and warning people of the potential risks involved (as always lol).
Hell isn't having Android on the Kaiser a risk anyways?
Sent from my AT&T Tilt using XDA App
Click to expand...
Click to collapse
Thats the thing though, i've actually killed a flash drive by reaching the max # of Read and Write cycles. For our nand's to be getting bad blocks means they have around a few years left as it is. I can't imagine what EXT4 would do to it lol. Also people who said that for hdd's must not know that hard drives include extra sectors. On our drives it just wear levels and marks the blocks bad as they go. It has no extras.
No hard drive has extra sectors. Hard drives rely on magnetism for their data entry of 1s and 0s, where as flash drives use electrical switches. Both have the same problem of bad sectors/blocks -- hardware failure.
If a hard drive sector fails, it's gone. No extra sector to replace it. Same with flash drives.
If sector 0 on a hdd were too fail, the drive fails entirely, because the BIOS reads sector 0 for the bootloader. What you're saying is if sector 0 failed a backup sector would replace, which has never happened in my 12 yrs of computer repair.
Sent from my AT&T Tilt using XDA App
Krazy-Killa said:
No hard drive has extra sectors. Hard drives rely on magnetism for their data entry of 1s and 0s, where as flash drives use electrical switches. Both have the same problem of bad sectors/blocks -- hardware failure.
If a hard drive sector fails, it's gone. No extra sector to replace it. Same with flash drives.
If sector 0 on a hdd were too fail, the drive fails entirely, because the BIOS reads sector 0 for the bootloader. What you're saying is if sector 0 failed a backup sector would replace, which has never happened in my 12 yrs of computer repair.
Sent from my AT&T Tilt using XDA App
Click to expand...
Click to collapse
They do have extra sectors for re-allocation. Well it won't recover the data of course but it would still be able to use it for data, it would mark it as bad and use a spare. When you partition a drive it doesn't use 100% of the sectors on the drive, more like 99.75% of them. Your right about the sector 0 thing. Although it has the extra sectors it doesn't mark it as sector 0. It basically just allocates the extra sector for use but to use it you would have to repartition the drive so it can use it.
See http://en.wikipedia.org/wiki/Bad_sector
If you want you can see how many spare sectors have been used by checking your drive's SMART status with speedfan under the reallocated sector count field.
I have less official experience but I built my first computer when I was 7 with assistance from my father, I am 20 years old, will be 21 in a couple weeks and I have been in the field roughly 3 years now. I only know stuff like this since I read articles about computer hardware alot lol.
Well anyways, ill take a look, but on my phone with no access to a PC atm.
Back on point, lol. From what I'm understanding if we were to switch to ext4 it would increase write cycles, decreasing NAND life.
But with the ext2 setup we have massive corruption no matter what we do. Which means we have to install Android constantly, which based on how many files are in /system, would increase write cycles briefly but exponiently because were writing to NAND on a grand scale, and plus with constant kernel flashes to update and hope for fixed corruption.
If ext4 really does help or even solve these corruptions it would mean less android re-installs, less data restores. Plus more in-frequent kernel updates, which will reduce write cycles anyways.
Plus if there is a performance gain, it would further reduce write cycles.
Am I right on this?
Sent from my AT&T Tilt using XDA App
I thought our NAND FS was YAFFS? EXT2 was only for SD if I recall. Faster speed doesn't mean less disc access, just means it is doing them faster. The only thing that would help is battery life as the cpu will be sitting idle more.
Oops yah meant YAFFS. I'm still on the iDroid mind set. They were using ext2 I believe, and recently switched to ext4 with their Gingerbread release.
Granted they use images inside the NAND, but that would still be the same thing regardless once the kernel is loaded.
What about YAFFS for /system and ext4 for /data. The kernel has that capability right?
Sent from my AT&T Tilt using XDA App
It should have that capability but I would really only use EXT4 on an SD card. YAFFS is the best choice for our kaisers right now since it is designed for NAND gate storage, whereas EXT4 is just a generic all purpose journaling filesystem.
The only problem with YAFFS is we didn't have the latest version for awhile and now we just have to figure out wtf were doing and get it configured right. There are a lot of variables that can be set.
Are we using YAFFS or YAFFS2? Both are designed for a specific NAND. Which one does our Kaiser fall into?
Sent from my AT&T Tilt using XDA App
hai there...
sorry to interupt u guys..
NWY,if there is time that when ext4 are available with system on SD as i saw that ext4 with data have are already looking great,could u guys make it for HARET as I'm lately using haret alot..
its a huge appreciation if anyone of u could do it...
thanks
Hi.. im using cyanogen with d2ext.. but now my phone is very very slow.. :-S will a swap partition help? Or What Else could the problem be? :-D
Sent from my HTC Desire using XDA App
SWAP partition is usually used when the RAM runs out and it doesn't increase the speed of the phone. It has the opposite effect....
the limiting factor is most probably the read/write access to your SD Card, using a higher Class Card (6 +) should increase performance.
I personally have my doubts if the sdcard will survive the many read/write cycles without a optimized (ssd) files system for a long time, but opinions differ here
Yep. Dirt slow and laggy unless you have a fast SD card. Things will improve quite a bit after the first few days of usage compared to the first, though.
------------------------------
- Sent via HTC Desire -
th3 said:
Yep. Dirt slow and laggy unless you have a fast SD card. Things will improve quite a bit after the first few days of usage compared to the first, though.
------------------------------
- Sent via HTC Desire -
Click to expand...
Click to collapse
whats the technical explanaition for that, some cache beeing build up or what?
Some accesss will definitely become cached, no doubt, but I'm not entirely sure as to the full happenings. I think the internal NAND management will move the data around to be more contiguous in placement and suitable to your access patterns for better performance and less misaligned accesses/fragmentation with some time. Clearing semi-full blocks and pages drastically helps NAND performance. The NAND filesystem you run can also have an impact.
I also think meletron's Ext alignment scripts help here when you have +20% of your NAND used up. Remember, NAND gets slower as it fills up, or more correctly, the more cells that have been written to (even if they are not in use anymore).
------------------------------
- Sent via HTC Desire -
Hello,
I am currently using a Rom with EXT4 and No Journaling and am experiencing Data Corruption. I want to switch to a ROM capable of Journaling. What is the difference between RFS and EXT4 with journaling on? And will EXT4 with journaling significantly impact my Phone writes so the internal drive fails faster than RFS?
Thanks
I read this article and saw that EXT2 is much more efficient for SGS Devices, why not use that instead of EXT4?
http://hkdennis2k.homeip.net/2010/11/04/reality-behind-rfs-lag-of-samsung-galaxy-s/
This debate raged a while ago when devs first began introducing ext4 into their roms. I can answer some of your post by saying that ext4 organizes your files much more efficiently for our flash based storage. RFS essentially treats storage like it is platter based (like a hdd). Without getting into much detail, ext4 locates and organizes data better than rfs. Ext4 is still better, even with journaling on.
but I heard that after about a year, the drive will fail due to too many read and writes because of EXT4 with journaling on. Is that true?
gokuman56 said:
but I heard that after about a year, the drive will fail due to too many read and writes because of EXT4 with journaling on. Is that true?
Click to expand...
Click to collapse
I'm not sure anyone really knows how long the drive will last. I'm sure it's way longer than a year. It will defiantly outlast your contract with Sprint.
It will definitely outlast your Sprint contract. And it's likely that it will not have any effect on your memory blocks at all. Noobnl had a thread a while back where users ran a test of their memory blocks. Many users that have been using ext4 for months and had flashed roms to their phones multiple times (I.e. 10x, 20x 30x). There was no increase in bad blocks at all over a few months of use. Our phones' storage operates just like a ssd on computers. Sure there will be wear but we are talking about 100k+ write cycles. I wouldn't worry at all about it.
Hi,
first-time-rom-installer here so bare with me if I'm asking stupid questions
I followed http://forum.xda-developers.com/showthread.php?t=1016084 so far with success, I've just finished partitioning the SD card but then I accidentally read something about ext4 would cause a shorter SD lifetime.
I'm not up to speed on all this stuff so logically I would go for ext4 (newest technology) but seen a lot of people saying there isn't noticable difference between ext3 and 4 is it really worth reducing SD lifetime?
Thx!
B
could you show us the info about ext 4 shortening lifetime
This shorting lifetime is a load of bull **** lol I have never seen one good evidence to this
I guess these are theories. I know leedroid has mentioned it.
I'm using VJ's CM10.1 ROM, it's good , but has random crashing issue. VJ gave a solution is using EXT3 instead of EXT4.
My question is, is there any noticeable difference between EXT3 and EXT4, when using A2SD? I'm using a SanDisk C4 SD, going to replace it with a SanDisk C10 SD. Would it cover the difference?
It's a slight difference, not really a huge one when we're working with small amounts of storage.
The real difference comes when we have an ext partition of several TB, like at linux computers. That's where ext4 shows its real speed.
abaaaabbbb63 said:
It's a slight difference, not really a huge one when we're working with small amounts of storage.
The real difference comes when we have an ext partition of several TB, like at linux computers. That's where ext4 shows its real speed.
Click to expand...
Click to collapse
Thanks mate. I'll give EXT4 a try again, if still crash, I'll convert back to EXT3.
Really thanks.