Ok, this may look like a stupid question, but with the trouble i got to make my unraid server work (with less drives than expected) and what i read on the forum about trouble of doing some stuff while building parity, i now wonder about multiple writes.

 

In case there is some stuff to be careful, i'd rather ask here before doing something potentialy bad.

 

So i have few external 1To drives that i want to transfert to my unraid server. I take all the files from one and drop them to lets say disk7. That process takes a huge amount of time, thanks to USB (12Mo/s). During that time, i can see that only disk7 and the parity drive are working, which is the wonder of unraid ;-)

 

Now, while the files are copying to disk7, can i safely take all the files from another external disc and drop them to lets say disk8 ? I just wonder, as the parity will change from the 2 different copy, that something bad happens on the parity.

I imagine 2 files at the same location on disk7 and disk8. Then as for each the parity drive would have to write its value at that position, isn't one will break the parity of the other if it happens simoultanously ?

 

Or is all this safe and unraid takes care of this simultanous parity build, so i shouldn't make myself some white hairs i already have anyway.

 

To go through this question, is it safe while building / checking parity to copy files to the array.

 

Let me be clear. If it can be dangerous with a very low % of chance (like 2 files copied at the same time at the same location that would break the parity build), it will be a no go for me and i won't do it, as i tend to fall in the very few % when there is one ;-)

 

Thanks in advance,

 

Just a very anxious guy 

No operations of writing or moving files will corrupt parity, regardless of how many are done at the same time, even while building parity, or rebuilding a disk based on parity and the other data disks.

 

With that said, losing power during writes to the array can corrupt parity, as it is possible for writes to one disk to complete before writes to the other.  For that reason, unRAID will always do a parity check if the array is not cleanly shut down.

 

I've had my array since 1995.  I've had one "parity" error, detected after a power failure, and that's it.  I use the array constantly, and it is used by multiple PC's on my LAN.    I now have a UPS on the server and it will cleanly shut itself down if an extended power outage were to occur. (I did not back then when the error occurred)  With good hardware, and good cables, and good power supply(s) errors don't just happen.

 

Joe L.

Or is all this safe and unraid takes care of this simultanous parity build, so i shouldn't make myself some white hairs i already have anyway.

 

To go through this question, is it safe while building / checking parity to copy files to the array.

 

It is safe to write to the array with multiple streams, multiple or the same drive.

Even while building/checking parity.

 

Each has it's performance implications.

While parity is being checked or built, some network streams may fail if they don't get serviced in time, but the data on your drives will be OK.

It's rare that this happens, but then again, I beat the hell out of my unRAID server.

 

I have 2 massive rtorrent seeds running, DVDshrink writing to the server and an AUTOGK running from another server.

I can still read streams from my network media player while this is all going on.

 

The only time I have trouble is if one of the rtorrents does a hash check and makes the server very very busy.

Writing a massive amount of data to the array while a parity build is going will elongate an already long process.  I'd (personally) let the parity build complete so that you are protected as soon as possible.  Given the issues you've had, I would run a parity check immediately after the build to confirm that all is well.

I'd (personally) let the parity build complete so that you are protected as soon as possible.

 

This is sound advice, I usually wait until a parity check is finished before writing to the array.

Reads I do not wait, bur writes I'll put off if I can. (unless it's only one stream. I.E. a single DVD rip).

 

 

Thanks all for your answers. In fact i wouldn't copy while building/checking parity, as truly this is a long process and anyway the load is full (it goes down to 10-15Mo/s). It was just to check this possibility, in case on day there is some writing during the process.

 

Right now i am filling my unraid server with all the data i had on external USB drives and my WHS. What i really wanted to do is transfert 2x 1To of data at the same time on different unraid drives, as i get for a single copy 12-14Mo/s and i know the unraid server can do better with just 3 drives working. So i expect no longer time doing 2x 1To at the same time. I just guess the parity drive will have a harder time as the heads will have to jump all the time instead of writing contigous area.

 

But now seeing what WeeboTech does at the same time with its unraid server, i am more than confident with what i wanted to do. Thanks again.

 

PS : WeeboTech : i wonder if you can move around and have space left at your home, as you seem to have all the possible hardware available

PS : WeeboTech : i wonder if you can move around and have space left at your home, as you seem to have all the possible hardware available

 

I'm single.. so you know how it is as a single guy with all sorts of toys all over the place...

I have a path that I follow hahahahaha!

 

I'll be cleaning some of that up by selling off old hardware on eBay soon.

 

If you look at my pic closer, that is only small portion of my desk.

It fits 3 monitors and keyboards across and has two levels. (It's capable of 6 monitor & keyboards)

There are two 6ft surfboard style tables on each side.

(was an old lan console from my job) Spans about 20ft wide

 

I have "some" pics here of various projects.

 

http://www.cotrone.com/rob/gallery/Technology/dscn0169

http://www.cotrone.com/rob/gallery/Technology?page=1

 

http://www.cotrone.com/rob/gallery/newmonitorsetup

But this only shows the right side.. There's also a left side...(so double it).

Plus a desk on my far extreme left for my Midi workstation.

OK, I'll admit... g**k....

 

 

OK, I'll admit... g**k....

You did not need to tell anybody you were single...  after seeing the pictures, we probably would have just assumed so.  If you have any long-term-friends of the opposite sex, they are probably geeks too.

 

I'm married, have been for nearly 35 years.  We do not own a Lava-Lamp... not even one.    My workshop might be as cluttered, but not my living room.  We don't even have a TV in the living room...  we do entertain a lot... real friends... most have a tough time with figuring out how to do e-mail.

 

But I do have a good assortment of toys... hell, I'm sitting here with three LCD screens in front of me as I write this on my newest LCD monitor, a really cool Viewsonic Optiquest Q24.  1920x1200 native resolution on a 24" screen is very nice. 

When I want a really big screen to browse the web, or, more importantly, watch a movie, I go downstairs to the theater.  I run 720p to a 110" screen.  ISO images on the unRAID server feed the HTPC in the theater and other media players in the house.

 

Being a geek is cool.  Having my wife ask me to put a LAN connection in our bedroom, so she can get to all the movies on our server and watch them on the bedroom TV, priceless.

 

Joe L.

Being a geek is cool.  Having my wife ask me to put a LAN connection in our bedroom, so she can get to all the movies on our server and watch them on the bedroom TV, priceless.

Oh Yes!!!

 

If you have any long-term-friends of the opposite sex, they are probably geeks too

I have one gal pal who was knew the core BSD kernel code in detail.

Most of the others roll their eyes 

 

:D

 

I had to call my wife in the bedroom to tell her i was very very very small player compare to you two guys ;-)))

(yes, in France it is nearly 1AM)

 

She thought i had too many hardware, now she knows some people can have much more, so finaly i don't have that much (may be i could get more ;-)  i doubt she'll bite)

 

I only have 2 lcd screen in front of me, and even if i put 30 RJ45 slots all other the house (2 in the bedroom, very hard to convince my wife on this one), i am very far from what you do ;-)))

 

But beeing a geek is very coooool ;-)

:D

 

I had to call my wife in the bedroom to tell her i was very very very small player compare to you two guys ;-)))

(yes, in France it is nearly 1AM)

 

She thought i had too many hardware, now she knows some people can have much more, so finaly i don't have that much (may be i could get more ;-)  i doubt she'll bite)

 

I only have 2 lcd screen in front of me, and even if i put 30 RJ45 slots all other the house (2 in the bedroom, very hard to convince my wife on this one), i am very far from what you do ;-)))

 

But beeing a geek is very coooool ;-)

Only two laptops and a monitor on the kitchen table, but there is a third laptop in the background on a rolling table in front of the couch.  The bright screen in the left in the back is a small HDTV on a swivel base in my den.

Big screen is in basement theater.

Here is a old picture, before I built a pair of large subwoofers to go under the sceen. :   I built all the speakers, and the screen....have a CRT front projector... woodworking  and electronics all tie into other hobbies.

 

Not a Lava-lamp in sight.  Being a geek is very cool.  Tell your wife she has it very easy.  (I do have to clear off the kitchen table when we have guests)

 

Joe L.

She thought i had too many hardware, now she knows some people can have much more

 

True, but then this is my career. I work from home allot, plus I have a consulting business and support other environments/communities.

So.. it seems all play, but it's work too!

 

 

Joe L...  I'm gonna call you Joe CooL

(I do have to clear off the kitchen table when we have guests)

 

Where does your wife eat breakfast?   

 

(I do have to clear off the kitchen table when we have guests)

 

Where does your wife eat breakfast?   

 

We usually sit side-by-side in the den, watching the morning news, having our morning coffee and breakfast there. She also usually uses the laptop there.  (She is only a tiny-part-geek, after hanging around with me for all these years.)

Joe CooL for sure !