Verifying SD Cards

Why Not? it is a very good idea to keep your /home on a desperate partition. also I would think with an SD card having a seperate data partition would help in the event of a partial failure. using linux file systems is also preferred as FAT does not support Linux permissions

I would have the following partitions

/boot fat32 - needs to be first partition / ext2 or ext4 (I like to avoid journaling on sd cards) /home ext2 or ext4

a swap partition seems to be unnecessary

Am 05.05.2016 um 08:47 schrieb druck:

I believe you've got the latter aspect backwards. Journalling exists precisely to avoid that kind of corruption. Non-journalling file systems like FAT corrupt a whole lot more easily and more thoroughly than journalling ones.

On Thu, 05 May 2016 12:17:34 GMT, alister Gave us:

Desperate?

/home/dan

.....

Gave us:

The whole reason for a journaling file system is so that an unanticipated data I/O channel disconnect or power feed outage has less potential to yield data losses.

Quite, and there is a clue that journalling might be a good idea on SD cards since the default Raspbian partition types are VFAT and ext4.

IIRC the initial boot partition has to be FAT for hardware-related reasons, but main partition can be any native Linux fs, so if non- journalling was a good idea the Raspbian maintainers would presumably have used ext2, but instead they went for ext4 which uses journalling.

Of course you use FAT32 only on cards/sticks/drives you want to use for quick worry-free interchange of files. The sneaker network.

Any use of those devices for permanent storage in a system should of course use the native filesystem on that system or a filesystem optimized for flash storage.

No, NTFS only journals filing system meta data, so while it can automatically recover what looks like a valid filing system, the contents of the files may be corrupted.

This is actually a lot more insidious than with FAT where if it is corrupted the filing system is broken and it will usually tell you straight away, and you can restore from backup.

---druck

On 05 May 2016 17:00:08 GMT, Rob Gave us:

Does not work for DVD iso image files or movie files over 4GB in size.

What is the list of "file systems which are optimized for flash storage"?

JFFS & JFFS2 are the first 2 that spring to mind.

declaimed the following:

The problem, in the case of flash memory, is that the journal will increase the number of write operations -- and on a card with, say, only two open allocation unit capability, the card may be swapping allocation units every for every small I/O operation -- and each allocation swap requires copying partial data from an old AU to the new one, freeing the old AU and erasing it so it is ready in the available pool. Cards with around 6 AU capability can keep the data file, inode entry (for Linux), bitmap, and journal "live" without closing AUs and assigning new ones from the pool.

IOWs; journaling file system on an SD card may 1) result in much slower performance on the 2-AU type card (optimized for streaming video on a FAT system: bitmap and data each taking an AU) and 2) much more wear leveling operations leading to premature card failure.

That's a bit silly. Neither FAT or NTFS guarantee writes to file data, and both will allow silent corruption of a written-to open file in the event of a crash (as in lost writes).

NTFS at least largely prevent crashes from corrupting files that were not being written to at the time of the crash.

"Native" filesystem? What file system is native to Linux?

On Thu, 05 May 2016 19:51:24 -0500, Robert Wessel Gave us:

Hey! Who said you have a right to talk about writes and then write it in here?! It's just not right. It is not the write thing to do.

Sneakernet doesn't let things like that get in the way - I used to download stuff and split it into floppy-sized chunks to take it home.

MINIX?

;-)

Den fredag den 6. maj 2016 kl. 04.23.16 UTC+2 skrev Rob Morley:

kinda, though now evolved into EXT4

-Lasse

I don't get it. Maybe I don't know enough about MINIX???

On Fri, 6 May 2016 02:45:07 -0400, rickman Gave us:

He thinks that his retarded "drill powered bicycle" is electronics.

And watch out, because the stupid putz adds groups to every post he makes like this.