Any Android and HDD Guru's

[keat]

Not Cubecart related.

 

I've scoured the net for 3 days trying to find a solution to a problem, I can't find the answer anywhere, even joined a forum to ask but no luck.

Then last night I stumbled on the answer through trial and error.

 

Does anyone know anything about Android, NTFS, exFat and SSD drives.

 

[Noodleman]

Yes... What's the question?

[keat]

I have a Nexus7 with a custom rom and custom kernel, in a car build, hooked up to a SSD, and a few other USB devices.

Despite the kernel being able to, I've never been able to get it to mount the SSD, so I've been using StickMount app, it works, but it's flakey.

I discovered last week, that the reason the kernel wont mount of it's own accord, is that Windows creates a hidden partition.

Of course Windows is where I built the partition. The drive is formatted exFat.

 

Using a Linux app, I deleted the hidden partition and now Android can see it, the data on there and it finally works as expected.  Yay

The problem is, everytime the tablet wakes up, is removed from the dock, the the ignition is recycled or the car cranked, the tablet loses the drive, which results in some sort of initialisiation routine when it comes back up. This takes about 30-50 seconds.

(i'm utilising .nomedia files)

 

Last night (using a spare HDD), I experimanted with an NTFS partition.

Low and behold, the NTFS partition doesn't go through the same drive scanning routine. The LED blinks once, takes 2 seconds, the drive is mounted and ready to go.

I think it's unlikely to the difference between the two drives, the exFat drive is an SSD, the NTFS is an old mechanical drive out of a laptop.

 

I don't understand why NTFS is instant and exFat takes 30+ seconds, and can't seem to find an answer.

 

Especially when everywhere I've read suggests using exFat

[Noodleman]

NTFS is a more advanced file system, it stores it's indexes in a different method to FAT based systems. f.y.i, you can manage partitions in windows using "Disk Manager", inclusing hidden partitions. assuming windows knows how to read the file system on the HDD.  It can probably read this file system faster because it's more advanced / indexed better. The real test would be to make the SSD NTFS and validate the issue isn't something firmware related with the SSD itself.

you should just be able to adjust the mount command being used for your media to the specific partition you want to use, the hidden one should be irrelevent in that context. In a table, when the SD/HDD is plugged in it does a scan of the drive. this takes a little time. it could be this that you are running into issues with. Assuming your HDD is powered from the tablet itself then it shouldn't need to cycle.

 

[keat]

I left the SSD data copying when i came out, so I'll know for certain later if indeed exFat is the issue, although I'm 99% convinced it is.

On the spare drive, I formatted NTFS, dumped a number of files on there and suffered no buffering issue, I then reformatted exFat, copied a similar amount of files and suffered some buffering

The tablet just doesn't provide enough power unfortunately, so it's all hooked up to a standard USB hub, connected to a 12v to 5v step down convertor.

 

[Noodleman]

You might find it better to use a large USB drive instead of an SSD. The hub itself could be a factor.

When the power drops to the hub (car restart etc) it's the same as unplugging the USB device, and plugging it back in again. This is likely causing your table to scan the media on the storage device as it's plugged in and is the main factor of the delay.

if that statement is true when the NTFS drive is full you should see similar behaviour. you really want a storage device that's always on.

because the drive isn't being "safely" powered off/unplugged it may be marking the file system on the drive as unclean, so it's doing a file system check when it powers back on. this happens a lot on FAT systems, but it also happens on NTFS. NTFS really doesn't like being unplugged in this way and typically you may run into more corruptions /issues due to it over time

 

Edited May 19, 2017 by Noodleman

[keat]

Interesting results.

Two hard drives in identical external cases.

175gb SSD formatted NTFS with about 150gb of data, takes 2 seconds to mount.

250gb SATA formatted exFat, with the same data, takes 40 odd seconds to mount.

 

Bearing in mind that the SSD was taking this time also when on exFAT.

There's one hell of a performance boost between exFat and NTFS, it's a no brainer.

[ayz1]

Replaced all our drives in desktops and laptops with SSD. The difference in performance even from an old laptop is amazing.

[Noodleman]

since it's not mechanical you don't have the seek time to find the sector, much quicker IO (recommend M.2)

the only concern with your setup is the loss of power to the storage and it not being unmounted correctly. based onthe storage limits, why not just get a 256GB USB stick so it's self powered?

[Dirty Butter]

No doubt that performance is better. But I thought I remembered reading that SSD lasts longer if it is not turned off and on repeatedly. Is that true?

[keat]

On 19/05/2017 at 3:07 PM, Noodleman said:

since it's not mechanical you don't have the seek time to find the sector, much quicker IO (recommend M.2)

the only concern with your setup is the loss of power to the storage and it not being unmounted correctly. based onthe storage limits, why not just get a 256GB USB stick so it's self powered?

I obtained the SSD through work, surplus to requirements, seemed like a natural choice for the car.