256GB Lexar SDXC for $19.99?!!!??!!! And free shipping?!! Is this even true?

[Askarus]

I got mine today

Size I can use is 239 GB.

What File System do you recommend for Pandora and Linux Computer.

Ext4 of exFat.

This reading and this one do sound interesting.

Will I get any noticeable benefit when using Ext 4 with these optimisations (I don't fully understand for now as my SD-card gives some strange results) of does exFat the job as well (+ Windows support)?

EDIT:

DD-TEST (quick 4GB)

exFat

Spoiler

dd if=/dev/sdc1 of=test bs=1048576 count=4000
4000+0 Datensätze ein
4000+0 Datensätze aus
4194304000 Bytes (4,2 GB) kopiert, 221,08 s, 19,0 MB/s

Ext4

Spoiler

dd if=/dev/sdc1 of=test bs=1048576 count=4000
4000+0 Datensätze ein
4000+0 Datensätze aus
4194304000 Bytes (4,2 GB) kopiert, 229,775 s, 18,3 MB/s

Here exFat seems to be a little faster.

I did make the partitions with mkfs.ext4 or mkfs.exfat.

In /etc/mke2fs I did delete the "has_journal" option

my settings:

Spoiler

features = extent,huge_file,flex_bg,uninit_bg,dir_nlink,extra_isize
auto_64-bit_support = 1
inode_size = 256

If anyone has experience with what is described in the articles above I would post my results here and appreciate some advice .

 

[DaMummy]

tigerdirect is one of the best etailers for computer stuff, id place my bet with more certainty that you were the problem, and not them

 

[_wb_]

What File System do you recommend for Pandora and Linux Computer.

Ext4 (or any Unix-like file system), so you can make symlinks, have owners and permissions, case-sensitive filenames, and so on.

I would probably make some partitions on a card like that: one big ext4 partition for data (200GB or so), one smaller FAT32 partition for compatibility (20GB or so), a swap partition (1GB or so) and another ext4 partition (20GB or so) to boot from.

 

[Askarus]

What File System do you recommend for Pandora and Linux Computer.

Ext4 (or any Unix-like file system), so you can make symlinks, have owners and permissions, case-sensitive filenames, and so on.

I would probably make some partitions on a card like that: one big ext4 partition for data (200GB or so), one smaller FAT32 partition for compatibility (20GB or so), a swap partition (1GB or so) and another ext4 partition (20GB or so) to boot from.

I also would like to use ext4.

Simply because FAT32 was half the speed when doing the speed tests.

If you say it's good for Sd-card then I will give it a try .

There is one more thing I don't understand: What's the actual size of my card?

GParted says it's about 239 GB.

Sysinfo does report it's 251 GB.

XFCe file manager says 223 GB left (says 256 left when using FAT 32 or exFat).

What's the right number?

Also when using Ext4 my Pandora Sd LED does some short blinking about every 4th second.

No real reason for that.

Other FileSystems don't.

Can I disable that?

 

[Wally]

It is a fake SD card.. So it's expected to be random and dodgy.

 

[DaMummy]

or it could just be the difference between bit and byte, and one filesystem taking up a larger percentage of space than another

 

[sebt3]

and one filesystem taking up a larger percentage of space than another

ext? filesystem reserve 10% of free space for it's own usage, while the preallocated space for FAT filesystem is a constant...

 

[_wb_]

What File System do you recommend for Pandora and Linux Computer.

Ext4 (or any Unix-like file system), so you can make symlinks, have owners and permissions, case-sensitive filenames, and so on.


I would probably make some partitions on a card like that: one big ext4 partition for data (200GB or so), one smaller FAT32 partition for compatibility (20GB or so), a swap partition (1GB or so) and another ext4 partition (20GB or so) to boot from.

 
I also would like to use ext4.


Simply because FAT32 was half the speed when doing the speed tests.


If you say it's good for Sd-card then I will give it a try .


There is one more thing I don't understand: What's the actual size of my card?


GParted says it's about 239 GB.


Sysinfo does report it's 251 GB.


XFCe file manager says 223 GB left (says 256 left when using FAT 32 or exFat).


What's the right number?

Define "right".

First of all, many programs say "GB" (1000^3 bytes) but what they really mean is "GiB" (1024^3 bytes). I assume of those three, Sysinfo is the only one that uses 10^9 bytes per GB definition. I personally have a lot of sympathy for 1024 bytes per kilobyte, but I have to admit that it makes no sense to overload the standard SI prefixes like that, so I reluctantly use the words kibibytes (KiB), mebibytes (MiB), gibibytes (GiB) now for those binary-based units.

For obvious reasons (you get higher numbers!) the storage media industry uses the SI units for a very long time now. A 256GB disk can store exactly 256 billion bytes. Also in networking it is common to express everything in SI units.

Anyway, the difference between GB and GiB explains why Sysinfo gives higher numbers.

Secondly, some programs report the total capacity, while others may report the capacity that is actually available for files (so not including the space needed for tables and journals etc). I assume GParted is talking about the total capacity (in GiB though), while the XFCE file manager shows only the actual available space for the user (probably also in GiB, although maybe in GB if you say it says 256GB when you format it differently). Sysinfo reports the available capacity, not the total.

Thirdly, on Unix-style filesystems, there is typically some fraction of the space (e.g. 5%) which is reserved for root. This is meant as a buffer against performance degradation when disks get very full, and to avoid that important processes run out of disk space because some user process has filled the disk. You can change the reserved space using tune2fs. You can't see how much of the free space is reserved in Sysinfo (it only shows how much is used, not how much is free), but in the XFCE file manager it's probably showing the free user space, subtracting the reserved root space. Of course filesystems like FAT that don't have permissions don't have the feature of reserved root space.

Also when using Ext4 my Pandora Sd LED does some short blinking about every 4th second.


No real reason for that.


Other FileSystems don't.


Can I disable that?

Is the journal properly disabled?

 

[Askarus]

All the long stuff 

Thanks for the explanation.

I did learn a lot about file systems the last 2 days .

Also when using Ext4 my Pandora Sd LED does some short blinking about every 4th second.


No real reason for that.


Other FileSystems don't.


Can I disable that?

Is the journal properly disabled?

Debugfs result:

Spoiler

debugfs -R features /dev/sdc1
debugfs 1.42.9 (28-Dec-2013)
Filesystem features: ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize

Some Forum Post did say I should see enabled jounaling in the "Filesystem features".

Don't remember the exact expression but it´s not in there.

So I assume it's off.

I think I did find the reason for the SD-access some minutes ago: mount option: "commit"

Kernel.org says:

Spoiler

commit=nrsec (*) Ext4 can be told to sync all its data and metadata
every 'nrsec' seconds. The default value is 5 seconds.
This means that if you lose your power, you will lose
as much as the latest 5 seconds of work (your
filesystem will not be damaged though, thanks to the
journaling). This default value (or any low value)
will hurt performance, but it's good for data-safety.
Setting it to 0 will have the same effect as leaving
it at the default (5 seconds).
Setting it to very large values will improve
performance

* means it's set by default.

Where's the Pandora's automount options for the Sd-cards?

I need to set it to a higher number disable it completely.

Can I set the automount option for some specific SD-Card?

Or do I have to make a custom entry in /etc/fstab for it?

If so will it still automount if I remove it and insert it again, or does fstab only work on a fresh boot?

EDIT:

I did add the commit=100 option to fstab.

Pandora does ignore this (did reboot).

Sd LED is still blinking every 5 seconds.

I can turn off that light if I have to...

Or stick with exFat for the moment as it's not the Sd I want to work with, only for Data (No symlinks and such is needed).

Anyways I would like to know why the fstab does not work as it should.

 

[Majin Wamu]

Hey guys, I actually once bought a 128 GB SD from china for like $14, and after like forever I finally received it. It is pretty slow but it does hold the 128 GB as it promised. I actually used h2testw_1.4 to check it. Thanks to someone who posted earlier in this conversation I was able to use that program to check if there truly was the stated amount of space as indicated on the card. I guess cards with a large amounts of space can be purchased at a awesome price, you just need to get lucky and find them in the right spots It's always a good idea to check the reviews on the products first before buying it, or check the reviews about the merchant.

 

[Askarus]

I wanted to do h2testw as well.

As I don't get more than average of 10MB/s it would take about 6-7 hours.

My Laptop is old and has no usb 3.0 or UHS card slot.

the card does seem ok so far and I don't want my Laptop to copy 250 GB of data for 7 hours.

EDIT:

I'm going the easy way now.

As I don't need the benefits of an Ext4 filesystem I did format the card to exFat.

I will try it again when I get a second card for all the PNDs and programs.

Maybe with the Pyra and a more recent Kernel.

I did learn a lot about formatting and such so it surely was no waste of time for me.

I don't know how much sense a speed test makes as even my USB 3.0 HDD only reaches about 30 MB/s average write speed with my old Laptop.

 

[DaMummy]

 

Hey guys, I actually once bought a 128 GB SD from china for like $14, and after like forever I finally received it. It is pretty slow but it does hold the 128 GB as it promised. I actually used h2testw_1.4 to check it. Thanks to someone who posted earlier in this conversation I was able to use that program to check if there truly was the stated amount of space as indicated on the card. I guess cards with a large amounts of space can be purchased at a awesome price, you just need to get lucky and find them in the right spots   It's always a good idea to check the reviews on the products first before buying it, or check the reviews about the merchant.

 

 

[Majin Wamu]

Um...k

 

[ingoreis]

My 512GB Stick has unfortunaly 64GB real Size.

I waited so long ang this was my first cheated Product.

In the Future will i be more aware before i buy

Even with 64GB ist that Stick ok for me.

Found out with a free lowlevel Format Tool over night and it hanged at the real End of the Blocks.

 

[Grench]

On my 128GB cards I found that ext2 actually gave me the best real-world performance when used interactively (active simultaneous reads & writes).

Your experiences may vary.