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
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Same here, would like to know,
Prowess said:
Same here, would like to know,
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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.
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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?
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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.
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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?
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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?
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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.
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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.
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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?
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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?
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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?
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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
I would like to know what is the best out of these two,or should i use both
angelo420 said:
I would like to know what is the best out of these two,or should i use both
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MTD still only uses whatever internal memory the phone has.
I myself have a Class 10 MicroSD and half of it is EXT lol.
I also have a class 10 16g. Also is it better to have a large ext cause i tried data2ext with a 512mb ext and it wasn't very good
I am using the custom MTD myself with CM roms. This combination works well for me and is pretty much no-fuss to deal with.
However, if I were using a rom with a much larger footprint, like the CR_Mod-2.13, I would almost certainly go the apps2ext route...
what do you guys mean by class 10?
class 2= 2MB per sec
class 6= 6MB
class 10=10MB
Its the transfer rate of your sd card.
I think it pretty much relies on what you have, I plan on getting a class 10 SD card and use both MTD and Data2ext. Though currently I simply have MTD and put the leftover /system memory into data for now. Class 6 or above SD cards are better for data2ext, otherwise you'll lag your phone badly. I use CM-7 with a bunch of stuff removed and added Genius button, so I have 130 allocated to /system currently. if you use a Sense rom using MTD is almost pointless because it uses the full standard allocation of /system memory. Data2ext would be optimal at this point. So it boils down to what you are/plan on using and what you plan on doing with data.
How big should the EXT3 partition be for data2ext.
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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 read in one of the ROM threads that Ext4 partitions shorten your SD cards life. Is this true? I'm awaiting the arrival of a new card, and I wouldn't want to shorten its lifetime too much...
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Myth, never seen actual proof. I'm using ext4 for 5 months now.
Ext3 and Ext4 add things like fancy journalling and stuff like that which make the filesystem faster, more flexible and robust etc, but involve lots of incremental writes to disk so yeah it will shorten its life.
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.
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Thanks mate. I'll give EXT4 a try again, if still crash, I'll convert back to EXT3.
Really thanks.