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Copying to a disk - speed?
show user profile  STRAT
Hi guys

I'm generally copying and backing up from my pc to external storage drives of various types via usb. I assume it's usb2 or above as my hardware is all fairly new tech

When i start the copying from pc to disk the transfer speed is always around 120-150 MB/s, but after 3 or 4 mins it fast slows to around 30MB/s and gets even slower. I find this the norm on most transfering disks i have, and, to a certain degree, from hard drive to hard drive.

Why is this? Why does it start at lightning speed only to slow right down every time? And how can i speed things up with my existing hardware?

Most frustrating every time





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read 629 times
1/30/2015 5:51:44 PM (last edit: 1/30/2015 5:52:52 PM)
show user profile  Garp
It could be that the speed is stable but its computation is wrong at the beginning of the transfer.
Just a thought while waiting for Stabby...




read 622 times
1/30/2015 6:02:03 PM (last edit: 1/30/2015 6:02:03 PM)
show user profile  Sir_Manfred
USB 2 speed is 480 Mbit/s which is 60 MB/s
USB 3 speed is 5.000 Mbit/s which is 625 MB/s

So you either use the USB 2 ports on your computer or your external harddrive is USB 2 or your harddrives writespeed is slowing it down.
The latter could mean that it goes fast in the beginning as it is filling up the Harddrives cache but once the chache is full, the writespeed slows down?

I'm only speculating while waiting for Stabby to take a stab at it.



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read 618 times
1/30/2015 6:11:37 PM (last edit: 1/30/2015 6:11:37 PM)
show user profile  STRAT
how can i know what usb/speed ports i have?

and if it is the cache filling up how can i sort this?


this isnt a new issue, i've had very similar problems over the years





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read 615 times
1/30/2015 6:36:18 PM (last edit: 1/30/2015 6:36:18 PM)
show user profile  mike_renouf
I think the general convention is that the faster ports on the motherboard (whether USB 2 or 3) have a blue plastic trim just inside the edge of the socket.

This is just what I've noticed - I'm happy to be corrected if that's not always the case.




read 600 times
1/30/2015 11:29:02 PM (last edit: 1/30/2015 11:29:02 PM)
show user profile  ScotlandDave
Throughput and bandwidth with these kind of things is definitely a major bottleneck in general system performance even with fast cpus and lots of memory etc etc.. SATA III, SSD's and USB3 all combine to take a huuuge step in the right direction..


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read 599 times
1/30/2015 11:36:19 PM (last edit: 1/30/2015 11:36:19 PM)
show user profile  Mr_Stabby
The initial high speeds is due to caching, most modern drives have at least 64MB of hard cache, also increasingly many consumer grade sata controllers enable ~10x the amount by default by commandeering the space from system ram but only on drives that are on the inside of the computer. The cache functions both as to store the data and to remap queries to where the data actually is at the moment even if its not physically on the drive.

That 30MB/s is the actual speed of the drive (quite typical for a low power external drive) and thats the speed the cache is emptied at before it can take another load. Great(semi fake) effect for transferring small files, makes no difference for large ones.

read 584 times
1/31/2015 8:07:32 AM (last edit: 1/31/2015 8:15:42 AM)
show user profile  STRAT
Thanks guys

So what is my fix? Auto clearing cache? A better external driven then? So what would you recommend on a budget?
And what about connecting to my pc, this has always baffled me. I normally just plug and play, unaware of connection properties.

At the moment 30mb/s takes ages when i got around 100 gig to transfer.

Ultimately, i'm looking for a solution to transfer speeds, whilst retaining my pc as it is. I can always buy a faster external drive.





SJLEWORTHY.COM











read 578 times
1/31/2015 10:58:28 AM (last edit: 1/31/2015 10:59:11 AM)
show user profile  Mr_Stabby
The cache operation is invisible to the user and mostly invisible to the OS so theres nothing you can do about that.

If you want quick sustained transfer then better drive is you're only shot. Modern consumer hdds still top out at around ~90MB/s, SSD's ~450MB/s. That's what you'll get with a straight eSATA connection, USB3 would still take a little toll up to ~10MB/s depending on how well its implemented. That is, of course, if the drive you're transferring from can keep up.

read 574 times
1/31/2015 11:43:55 AM (last edit: 1/31/2015 11:43:55 AM)
show user profile  joelr
I I think that the best solution for you is an external raid 0 drive.
Well that depends on the amount of data you need to backup. If it's only 100 gigs then I would go on a 2 drives in raid 0, that will give you the speed you are looking for. If you have esata on your MB, or you can put as a PCI card you will get better speeds then usb2.
If you need more the 100gigs, and you want more drives in this array, maybe look into raid 5.
There is another post here regarding external esata raid drives that you can look into.

I'm talking maybe about something like this: http://www.newegg.com/Product/Product.aspx?Item=9SIA0AJ1097956&cm_re=Raid_esata_usb-_-22-145-418-_-Product

Joel



read 571 times
1/31/2015 1:27:48 PM (last edit: 1/31/2015 1:27:48 PM)
show user profile  Mr_Stabby
I recommend never to store important data on raid0 without a backup. That said, a raid0 capable enclosure + drives will cost you more than an ssd, you'll get more space but you lose out on speed and reliability(somewhat).

read 564 times
1/31/2015 3:49:16 PM (last edit: 1/31/2015 3:49:16 PM)
show user profile  STRAT
thanks again chaps.

i plugged the drive into a new pc i have, which has a higher spec (and those blue usb 2 ports you mentioned Dave ;) and after a couple mins of the cache settling down the speed started off as before at about 150 mb/s and level off at about 80. give or take 3 times faster than my other machine.

for 50 notes worth of drive i can live with that :)



also, even though im on a pc, i formatted my external drive in mac format and use MacDrive software as my interface.

Must admit, even though i'm a pc guy through and through, my experience with the mac os over the years does make me envious sometimes, which is why i find backing up to a mac disk infinitely more stable than using standard pc formats. The amount of delayed writing, slow writing and even mid writing crashes were all to regular i'm afraid.

just my opinion.





SJLEWORTHY.COM











read 558 times
1/31/2015 5:18:19 PM (last edit: 1/31/2015 5:20:18 PM)
show user profile  Dr_Jim
Hey Strat,
I went through this recently.....and also when setting up a video drive system

Bottom line from my reach (and testing) is that USB is shared. Period. If you need "sustained" fast throughput then each drive needs it's own channel....I went with Esata and everything became much more consistent.

For backing up and such you may not care as much.....
But even my word/project drives are RAID 0 Esata (backing up nightly to a WD 8TB RAID 1).
It's nice for files and such to open so fast....
read 508 times
2/3/2015 10:32:06 AM (last edit: 2/3/2015 10:32:06 AM)
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