[Wolves] backing up methods

Stephen Parkes sparkes at westmids.biz
Fri May 8 13:24:24 UTC 2009


2009/5/8 Adam Sweet <adam at adamsweet.org>:
> DragonMaster wrote:
>>> Ah, hang on...  Is it a USB hard drive or a USB flash drive?  Sorry I
>>> can't remember.  Though I think you said it's a 1TB drive so it's got
>>> to be a hard drive.  It's alright, the alrm bells started to clamour
>>> as ext3 being a journalling system would kill a flash drive in not too
>>> long a period.  It's fine on a proper whirling platters hard drive
>>> though :-)
>>> --
>>
>> Really? why's that - surely the journal only gets updated on a write, so
>> you would get a few more writes than on an ext2 partition, but nothing
>> disastrous?
>
> Well the journal would be updated for every write and I believe the
> location of the journal is always in the same place on a disk, which
> means that every write to the filesystem means a write to the same
> groups of cells occupied by the journal. The default ext3 filesystem
> behaviour is to update a file's access time on every read, which means a
> journal write, so every time you read or write a file, you write to the
> journal.
>

It was certainly the case when I discussed this stuff with Raf at xinit
at the expo in about 2000.   At the time they where developing solid
state servers and reiserfs and other journaled filesystems (ext3
wasn't finished jono, lee and myself chatted to Alan Cox about it and
Hans Reisers 'problems' that night ;) ) would kill £35000 solid state
hdd's in hours!

Not a project I could afford to make mistakes on and as everybody
knows I'm a pile of mistakes that formulate into genius or explode no
safe ground :)


-- 
Steve 'sparkes' Parkes



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