SD card partitioning and other low-level operation questions

[cmags]

Note to Mods: Much of this is asking specific questions regarding my ThunderRom config, but the discussion it (hopefully) prompts should be good info for all. But if it should be moved to the Hacks/Mods section, it don't bother me none.

So I just received my SanDisk 8GB Class 4 SD card and before I copy my data to it, wanted to explore some options for partitioning.

I've read various info and it seems that if one does manually partition the SD card, you leave an ext3 partition of 256-512MB for apps, 32MB for swap, and the rest leave as FAT32 for user data/media.

I'm currently running ThunderRom 1.5 w/ the Xionia 005 kernel. I already have Apps2SD via TR (managed using Advanced SD).

Now if I were to set up an ext3 partition on my SD, would this be beneficial to me? I notice that when I choose to move an app to the SD, it doesn't *completely* move. For example, there will be a 5MB app on the phone that I move to SD, and afterwards, it reports maybe 800KB still on the phone. If I created the ext3 partition, would this leftover data be put there or remain on the phone?

Are there any advantages to swap on the SD? 32MB on the 8GB card is nothing, but freeing 32MB on the phone, if it would give it back to me in the phone data, would be nice. Is there a speed tradeoff? I realize that if the linux swap partition were on the SD and the SD failed or stupid me unmounted it for some reason, bad things may happen. Can anyone expand on that however?

While on the topic, what about the cache? In TR I understand that the dalvik-cache is already moved out of /data and into /cache, which helps give us that 160MB free space in /data. Can this cache be moved to the SD as well? Is there a point? Can /data then be expanded or are we stuck with what it is?

Just trying to step up my knowledge of the low-level operation of the phone. Thanks ahead of time.

 

[hamagc]

damnit, closed my first response to you on accident without posting it. trying again. if anyone finds misinformation in here, please let me know.

android (stock) uses rfs filesystem. if we want to use ext3 i believe we need to format the internal for that. i have yet to see that setup for our device. without the phone being ext3, i don't believe ext3 will work properly on the sdcard. so when you move apps to sd via froyo, it won't utilize ext3. it'll still put everything in the android.secure folder on your sdcard.

i believe android leaves a protion of the app on the phone when you move it to sd. i would imagine a drm issue (so you can't move them to sd, pull them off and upload them for everyone else.).

as for swap, until we start formatting in ext3, theres no real need for a swap partition.

with apps2sd, when you have your apps on the sd and remove or unmount the sdcard from the phone, all apps that are on the sdcard will disappear from the phone. once it is inserted and mounted by the phone, the apps will reappear. this is why they say not to move widgets and lwp to the sdcard.

dc is moved to cache and frees up like 40-60mb or something like that. i imagine it can be mvoed to the sdcard but there is plenty of room in cache for it that it wouldn't really make a difference. also on sdcard, when you remove the sdcard, the dc will go with it prompting the phone to rebuild the dc. if the sdcard isn't mounted, i could see this causing some issues with android.

as for a bigger /data, i don't think it is possible or needed. i have 150mb on sdcard from moved apps. i have about 175 apps installed (according to titanium backup, number of app data elements: 175) and have 36.73mb available in /data still (out of 165). i'm on a stock from with a dalvikcache to cache mod applied. this includes some big things such as need for speed shift, quake 3, the sims, both anrgybirds, winds of steel, turbofly 3d, a quite a few other things.

hope this helps!

(see post below regarding rfs, yaffs2, ext3, etc)

 

[cmags]

Immensely. Gave me some good info to feed the brain, and even more importantly, let me know to just copy my data to the new card and get it loaded.

Interesting that the phone isn't ext3. I'll have to read up on rfs. This is specific to the Optimus right?

 

[hamagc]

i don't believe so. i believe all stock androids come rfs. people have just converted them to ext3. i believe ext3 runs smoother and faster than ext2 or rfs.

actually i may be mistaken on this. android defualt uses yaffs2. rfs is used by samsung specifically.

 

[KSmithInNY]

actually i may be mistaken on this. android defualt uses yaffs2. rfs is used by samsung specifically.

Correct. RFS is a samsung thing. Most (read, all) others use yaffs2. The exception now being the Nexus S which uses EXT4 if i'm not mistaken?

 

[Disaster]

Froyo just puts one big fat32 partition on the card. No reason or advantage to do anything else. I just unmounted the stock 2Gb card and popped in the new one allowing the phone to format it. Then I copied all the contents from the old 2Gb card back to the new 16Gb card...overwriting all files on the new card. All previously moved apps work perfectly.

 

[cmags]

Yea that's what I've done now with two card changes. Strange to note tho, each time I did change cards, everything transitioned smoothly except for the ringtones and notifications. They all come back choosing random mp3s that I loaded on the card. Happened twice or I would have chalked it up to black magic... Just an observation.

Sent from my LS670 using Tapatalk

 

[Lordhungus]

If I were to partition a new, freshly FAT32 formatted sd card (Class 4) with an EXT 2 partition, would a stock, unrooted phone use the partition for apps? This is my daughter's phone, so I have reservations about rooting it. Also if Froyo would use the EXT 2 partition, would using the custom recovery on my phone (not an Optimus) to create it cause problems?

NVM everything I posted above. Running Lego Rom now! After all was said and done I was saddened to see that A2sd isn't supported (yet?). Well I have a partition waiting if somebody gets A2sd working.