On 05/21/2017 12:04 PM, Chris Schanzle wrote:
On 05/18/2017 11:39 PM, Ram Ramesh wrote:
On 05/18/2017 08:34 PM, Adam Goryachev wrote:
On 19/05/17 07:37, Ram Ramesh wrote:
Any one have a method to backup large volumes like md raid6 (16TB)?
Since the backup will not fit in one disk (in many cases and mine
too) I am wondering, if there is a known/easy technique to backup
using multiple usb hard drives. I googed and found a few fancy
backup utils/systems like Amanda etc. They are overkill for me. I
am choosing not to back up simply because of the complexity of
setup as the data in my RAID volume is NOT precious and can be
replaced with a week of effort.
If any one can think of some thing simple, please point me to it
and I will do the reading to figure out.
I suppose it depends on what you want to achieve. There are various
options such as mirroring to another raid6 array (ie, RAID60) but
really that isn't a backup, it's another replica.
I use backuppc for my backups, it works well under linux with rsync,
I'm sure there are many various options (including amanda which I've
used in the past). Ultimately, it depends on your requirements,
backups vary significantly depending on needs/etc.
Regards,
Adam
Here is a summary of what I like to do. I want to backup files on to
(multiple) disks that will be loaded on to a USB dock. Simple one to
one copy is all I am looking for. I am not interested in full vs.
incremental or keeping versions of files for restore. My data is just
movies and songs. All I want is a SW that understands links (to avoid
duplicates) and copy files in batch on to multiple disks. I want
content of each (backup) disk to be independent. This way if one
backup disk dies, I have all other files unaffected by this failure.
The only reason I did not try multi-volume tar is the lack of
independence across disks.
I suppose this is a backup question rather than RAID question. I
asked here because the size of RAID volumes make it impossible to
back up to a single drive and this is a more common problem RAID
world rather than general user forum in a backup mailing list.
Ramesh
Thanks for the additional info on your requirements.
Rsync will be your best/fastest tool, as writing 16 TB of data over
USB will likely take days for a full backup...and that seems silly
when you probably already have 90% of the data already.
If one drive failures are a concern, why not use RAID5 for your group
of USB backup disks? Might take you a bit more effort
starting/stopping the array, but I'm sure you'll enjoy the large
single volume/filesystem in the long run. Use a fairly large
--chunk= size for your large files. I have had very positive
experience with XFS for large multimedia filesystems (mythtv user and
20TB backup servers).
If the drives you choose to use are desktop grade, be sure to increase
the timeouts. Search this list archives for Chris Murphy's subject:
"Re: URE, link resets, user hostile defaults".
The only problem with raid is that all disks need to be present to
create md. I only have the ability to load two disks and the disks are
fairly small compared to RAID l (3TB vs. 16TB) So RAID5 won't work.
Besides, I do not want to use RAID to backup RAID as my worry is md
going bad and preventing access to my files. It is not disk that I am
worried about mdadm layout and requirement that many disk to be alive to
get even one file.
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