On 5/23/2013 7:14 AM, saeedeh motlagh wrote:
thanks for your reply.
you know i have a sensitive server and unfortunately it is located some
where that power outage happens much. so i want guarantee my data and avoid
data lost and file corruption in my server.
Get a good reliable UPS. Test it regularly, the batteries do fail.
Test to make sure that it will work, unplug it and let the computer
drain the battery to time it. Consider that the battery will degrade
over time. One thing google does is put a 12V battery inside the
chassis to help with the power backup, you might look into it.
i do not have any problem in RAM and hardware.
i don't know which approach is more suitable for my server. using
soft-update or ZFS. please help me to select the best one.
If power failure is an issue, you have no guarantee of data loss
protection unless you use networked storage to a safe place. UFS soft
updates protects against file system corruption in case of power loss,
no guarantees of individual file consistency. ZFS guarantees no silent
failures, it doesn't guarantee protection, only that you'll know about
it. There is no filesystem that can guarantee you won't lose data in a
power failure. Hard drives are known to lie about what's been
physically synced to disk out of cache in order to improve speed. If
the power goes out at the wrong time, you can lose data. ZFS can find a
corrupted file and tell you, everything else won't. If you have a back
up of that file, you can restore it.
thank you so much
On Thu, May 23, 2013 at 4:28 PM, Warren Block <wbl...@wonkity.com> wrote:
On Thu, 23 May 2013, saeedeh motlagh wrote:
hello every body
i have a question about fixing file corruption in freebsd.
now i have freebsd8.2 and some times file corruption happened on it. this
issue has a heavy cost for me and i want to avoid it or fixit it
completely. so my question is:
is it better to upgrade my freebsd to 9.1 and use soft update or migrate
from UFS to ZFS?
That's a judgement call, which means "it depends".
i heard so much about soft update -that is added in freebsd9.1- which can
fix file corruption in acceptable way with low cost but i don't know how
much is reliable and efficient.
Several things:
Soft updates have been around for quite a while.
Soft updates journaling is the new addition.
Neither of these address file corruption. Their purpose is to make sure
the filesystem does not get corrupted, but individual files could still
contain bad data.
in the other hand, i think migration from UFS to ZFS can be another
solution. as i read ZFS is is created to solve all the problems related
integrity file system. is it reliable enough in comparison soft-update?
now, i want to know which solution is better and why?
Again, it depends. Does the target system have enough RAM for ZFS? If
the file corruption is due to a hardware problem or an application writing
bad data, no filesystem can prevent that.
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