Hello
I have spent sometime going through some past articles on partitioning. There are still questions in my mind. I hope someone could help me clear up this.
I gather it's good to have an external partition where it is used to store apps and cache. It is stated that optimal size for it is abut 512mb - 1G as ext3/4.
Is there in fact reason to stop me from converting the whole SD to ext3/4 and get rid of fat32 altogether? I am linux based and I really don't care much about visibility of files at all. It seems that the current ROM works with 2 partitions: one fat32 and the other as ext3/4 and we typically allot a lot more for fat32. What's the primary reason behind this decision? Would there be some system stuffs that rely on fat32 to function?
As far as sizing is concerned, I would like to have some real reasons why things have to be arranged this way (with fat32 as a dominant partner) instead of going all the way to ext4
Even if You will format Your sd-card using Your phone You will see, that it will be FAT partition as well. So it's basic partition which android use to save photos, movies and all apps keep their data folders (f.ex. sms backups, apps backups etc). Ext partition is also not recognized by PC with Windows, so there isn't any way to use it as a storage device. And I think that similar is with android - I don't think if f.ex. music player will recognize Your music files on ext partition. But it's just my opinion and I may be wrog.
Related
I did a search but couldn't find anything specific... so my question is, should I upgrade my ext3 to ext4? if so why? if not.. also why
gmelchert said:
I did a search but couldn't find anything specific... so my question is, should I upgrade my ext3 to ext4? if so why? if not.. also why
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No. Most (all?) of the new 2.1 test build leak based ROMs do no support a2sd on ext4. On (most of) these same builds ext3 works automatically.
danknee said:
No. Most (all?) of the new 2.1 test build leak based ROMs do no support a2sd on ext4. On these same builds ext3 works automatically.
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thanks thats good to know!
I know most of you are not Linux users so let me break this down for you:
EXT2: Very basic filesystem when it comes down to it -- think of it as a Unix filesystem you could place inbetween the likes of FAT32 and NTFS. I would nearly argue that this is the modern equivalent of FAT32 (which really really needs to die). We really shouldn't be using FAT32 but lack of native windows compatibility stops EXT2 from being a candidate for this usage.
EXT2 is highly recommended for your flash card. It won't over stress it and there aren't many alternatives that are better these days unless you're dealing with raw flash, which you'd then use something like YAFFS2 or JFFS2. The flash in compact flash cards is not raw flash.
EXT3: Picture EXT2 with a journal. It is backwards compatible with EXT2 (just doesn't read the journal).
A journal is NOT recommended for flash devices. (At least when the filesystem was not designed for raw flash and isn't tuned properly like YAFFS2 and JFFS2). Do you really want your phone to write all the metadata to the journal first and then to the filesystem? That's a ton of unnecessary I/O. If it has full journaling enabled you're writing all your data twice. This is not a good idea for your phone. This is one reason why NTFS has not become a standard for flash devices: Journals on flash are bad unless it's designed for flash from the ground up.
EXT4: same as EXT3 but is a copy-on-write FS with delayed allocation (holds data in memory longer before writing to disk to be more efficient / prevent fragmentation), increased number of files and size of files (more than a phone ever could need in our lifetime), etc. Some improvements across the board but not backwards compatible with EXT3 anymore if you're using the delayed allocation. Most likely to eat more memory on your phone.
This is completely unnecessary for a phone and really does not fit your needs. I don't understand why anyone would attempt to use this unless they simply thought "4 is bigger than 2 or 3 so it must be better!"
So there you have it. I may have forgotten a minor detail here or there, but this is the gist of it.
feld said:
I know most of you are not Linux users so let me break this down for you:
EXT2: Very basic filesystem when it comes down to it -- think of it as a Unix filesystem you could place inbetween the likes of FAT32 and NTFS. I would nearly argue that this is the modern equivalent of FAT32 (which really really needs to die). We really shouldn't be using FAT32 but lack of native windows compatibility stops EXT2 from being a candidate for this usage.
EXT2 is highly recommended for your flash card. It won't over stress it and there aren't many alternatives that are better these days unless you're dealing with raw flash, which you'd then use something like YAFFS2 or JFFS2. The flash in compact flash cards is not raw flash.
EXT3: Picture EXT2 with a journal. It is backwards compatible with EXT2 (just doesn't read the journal).
A journal is NOT recommended for flash devices. Do you really want your phone to write all the metadata to the journal first and then to the filesystem? That's a ton of unnecessary I/O. If it has full journaling enabled you're writing all your data twice. This is not a good idea for your phone. This is one reason why NTFS has not become a standard for flash devices.
EXT4: same as EXT3 but includes is a copy-on-write FS with delayed allocation (holds data in memory longer before writing to disk to be more efficient / prevent fragmentation), increased number of files and size of files (more than a phone ever could need in our lifetime), etc. Some improvements across the board but not backwards compatible with EXT3 anymore if you're using the delayed allocation.
This is completely unnecessary for a phone and really does not fit your needs. I don't understand why anyone would attempt to use this unless they simply thought "4 is bigger than 2 or 3 so it must be better!"
So there you have it. I may have forgotten a minor detail here or there, but this is the gist of it.
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Nice explanation.
You left out the part about how apps load faster from RAM then they do from any sd card. The people running slower sd cards especially may potentially be experiencing a performance decrease due to a2sd.
I have abandoned a2sd because after I load every app that I use, (plus 10 random ones) I still have room left. Then I use the extra half a gig on my sd card for another 5 cds worth of music.
feld said:
I know most of you are not Linux users so let me break this down for you:
EXT2: Very basic filesystem when it comes down to it -- think of it as a Unix filesystem you could place inbetween the likes of FAT32 and NTFS. I would nearly argue that this is the modern equivalent of FAT32 (which really really needs to die). We really shouldn't be using FAT32 but lack of native windows compatibility stops EXT2 from being a candidate for this usage.
EXT2 is highly recommended for your flash card. It won't over stress it and there aren't many alternatives that are better these days unless you're dealing with raw flash, which you'd then use something like YAFFS2 or JFFS2. The flash in compact flash cards is not raw flash.
EXT3: Picture EXT2 with a journal. It is backwards compatible with EXT2 (just doesn't read the journal).
A journal is NOT recommended for flash devices. (At least when the filesystem was not designed for raw flash and isn't tuned properly like YAFFS2 and JFFS2). Do you really want your phone to write all the metadata to the journal first and then to the filesystem? That's a ton of unnecessary I/O. If it has full journaling enabled you're writing all your data twice. This is not a good idea for your phone. This is one reason why NTFS has not become a standard for flash devices: Journals on flash are bad unless it's designed for flash from the ground up.
EXT4: same as EXT3 but is a copy-on-write FS with delayed allocation (holds data in memory longer before writing to disk to be more efficient / prevent fragmentation), increased number of files and size of files (more than a phone ever could need in our lifetime), etc. Some improvements across the board but not backwards compatible with EXT3 anymore if you're using the delayed allocation. Most likely to eat more memory on your phone.
This is completely unnecessary for a phone and really does not fit your needs. I don't understand why anyone would attempt to use this unless they simply thought "4 is bigger than 2 or 3 so it must be better!"
So there you have it. I may have forgotten a minor detail here or there, but this is the gist of it.
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I had never thought about this before. It makes a good point, flash memory dies after x ammount of Reads and Writes. Given it's mostly in the 100 millions, but it does more reading and writing than you would think it does, and you are effectivly killing the memory card twice as fast.
Good thing these things are relativly cheap.
this is all really good to know. thanks. i spent $100 on my sd card so maybe i should just foemat the whole thing to fat32.. (its class 10) while you guys are here, what exactly is the use of swap?
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gmelchert said:
this is all really good to know. thanks. i spent $100 on my sd card so maybe i should just foemat the whole thing to fat32.. (its class 10) while you guys are here, what exactly is the use of swap?
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SWAP = Page file in the Linux world. From what I have read (This may have changed since then) We don't have the ability to use Swap yet.
danknee said:
You left out the part about how apps load faster from RAM then they do from any sd card. The people running slower sd cards especially may potentially be experiencing a performance decrease due to a2sd.
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You're right -- apps do load faster from RAM. However, when you're not using a2sd the applications are not on the phone in "RAM". They're in a flash chip inside the phone -- just like on your sd card. The performance should be nearly the same when you're using a2sd as it is when you're not using it.
The only reasons why a2sd should be slower are:
1) You have a cheap, slow SD card
2) The interface from the SD card to the phone is cheap and slower than the internal flash chip's interface. It was just a cheap design choice the manufacturer made.
3) The internal flash is simply faster from it being a better flash chip
feld is right. Using anything other than ext2 for the apps2sd partition boggles the mind. I have no idea why people insist on a: providing support for it and b: encouraging people to do it.
Ok, provide support for it for the people who know what they're doing/just want to do it for the hell of it, but having a journalled filesystem on an sd card makes no sense whatsoever.
As feld says ext4 uses up more RAM than ext2, which might be all well and good for things like the N1/Evo/Desire etc but not everyone has such a RAM beefy phone.
Besides that, the bottle neck in speed is the SD card/controller. No "faster filesystem" is going to improve that. Adding more IO is only going to slow things down.
Moved as not Android Development.
Unless I'm misunderstanding...It's true that mounting your SD card in Froyo with apps installed to the FAT32 partition means that your phone can't access applications on that FAT32 partition right?
Yeah, you're right. That's why Google doesn't support having Widgets, keyboards, and other always running services on the SD card. Its a trade off, but a sensible one I think. Having two volumes on the SD card is likely to confuse inexperienced users. Also they need to decide ahead of time how much space to reserve for apps on the sdcard. Too much and they can run out of room for their other data, not enough and they are right back to the old problem of no room for apps.
Anyway, there's no reason you need all your apps on your sdcard. As long as you can put your big apps like games and Google earth on SD you should have plenty of room for other stuff on internal memory.
No, you're not the only one who likes it.
I sure hope that ROM creators leave the option of using old Apps2SD.
That is the only reason I switched back to 2.1
I'm going to be using a 16GB SD card and want to make sure I have a lot of space for apps. I've seen many mentions of increasing the size of the 4th partition, namely the SD Card partition. But would it do any harm to increase the size of the Data partition (partition 3) which I believe is where the installed apps live? I really don't need a ton of SD card space since I won't be storing a lot of media on it or anything.
Is there a way to switch the sdcard / sdcard-ext folder names to make the external sdcard the primary one? Or is there any other way to set the primary sdcard?
Thanks!
I was disappointed to see the phone force you to use sdcard and then renamed my microsd card to sdcard-ext. It made it quite a bit of a hassle to restore programs or use the backup features of other apps.
I know its been done on some tablets running 2.3 (My old Viewsonic G Tab). On those you had to edit the vold.fstab to mount them the way you want.
I'd love to do this too. I made a lot of songs available offline in Spotify, synced some mp3s etc and it all ended up on the internal "sdcard", not my 32gb class 10 Patriot MicroSDHC (which works perfect with the D3).
The same goes for most apps.
If someone has experience doing that please tell us how to do, I'm not too experienced in such Linux filesystem things. THANKS!
+1 this is very annoying.
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/etc/vold.fstab seems to be the right place to change it, like mentioned above. However I think the risks are little, I wouldn't be the first who tries out ... at least not before an SBF is available.
And I cannot fully assess what it means for future updates, if and how it has to be undone then. I'd rather recommend to live with this naming.
Thanks for explaining that und danke.
I'm more curious to see if we can remove the space allocated to "sdcard" and merge it back with the internal program storage, then when I drop my actual sd-card in, it mounts as "sdcard".
Possible? Or is that a rom only thing.
Does this link help?
Partitions for the x2
I'm afraid I'm not experienced enough to dare to try it ^^
My file system is totally confused. When I browse to EMMC from a file manager it goes to my SD Card. If I browse to SD Card it actually goes to the internal drive.
I've had my rooted Nook Color for about 5 weeks now (CM7 booted from a SD card). Everything was working great until I tried installing some different launchers. I tried GoLauncher, Zeam, ICS, Honeycomb and maybe one more. The default was ADW. Maybe I confused the system by constantly switching from one to the next but at some point the system crashed and I rebooted.
Once rebooted I noticed that many of the games I installed told me I needed to redownload their data files. I looked on my card, through my Mac, but the original files were still there. Turns out the Nook now installs apps on the internal drive rather than the card as it had been before.
Wouldn't be so bad but, as mentioned earlier, the file system is confused. When i need to manage files I've loaded on my SD card I have to browse to EMMC and vice versa. Makes my head spin.
Is there a way to fix it without starting from scratch? I'm using CM7.2.0.
Thanks for your help
That's not a bug, it's a feature. Anyway, what you likely did is Settings -> Cyanogenmod Settings -> Application Settings -> Use internal storage (checked). If you do this, then it swaps the mount points for the SD and the internal memory, so the SD card is mounted at "/emmc" and the internal memory is mounted at "/sdcard". See the first post in the thread in my sig for more information about this.
If you really want to return it to the original way, wasting 5G of internal storage space, then you can uncheck that box in the settings and it'll go back to normal.
Thanks for pointing that out and glad to see there's an easy fix. Seems a bit confusing though, like it's renaming your hard drives or something. I had been using the internal drive for storing media files, video, music, comics. Does it matter where apps or files are stored?
false1 said:
Thanks for pointing that out and glad to see there's an easy fix. Seems a bit confusing though, like it's renaming your hard drives or something. I had been using the internal drive for storing media files, video, music, comics. Does it matter where apps or files are stored?
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Well, the "fix", IMHO, is to leave it with them swapped.
Yes, it matters where apps are stored and it matters what is mounted at /sdcard. Apps use space on the /sdcard partition for settings, temp storage, downloads, etc. Mounting that 5G partition at /sdcard instead of /emmc allows these apps to use that space rather than cluttering your actual SD card. And apps are going to wind up on your 1G partition, not on either the /sdcard or /emmc mountpoint.
You can go read up in my guide on my recommendation on how to best use this space. The normal way is inefficient and wasteful of internal memory, IMHO. But you know, maybe you like it that way
mr72 said:
You can go read up in my guide on my recommendation on how to best use this space. The normal way is inefficient and wasteful of internal memory, IMHO. But you know, maybe you like it that way
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I think efficiency is more in how you choose to utilise the spaces rather than fundamentally in which switch option you use. For example, I choose to completely fill the 5GB of internal with sound and picture media as they get included in the normal app scanning process. Leaving the SD card to hold yet more media, app data and back ups.
It's still good to have the choice offered by the switch.