omicrolibre
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Storage server with RAID on multi micro sd cards

Tue Nov 03, 2015 4:16 pm

hi !

i want to create a storage sever with approximately a capacity of 8 or 10 To to share data with my friends by internet (i have more than 100 Mb/s upload connection). But i have not enough money to choose a hard drive solution, it's why i thinking about a RAID solution with micro sd cards since i seen that we can found on ebay a 512 GB micro sd card at less than 10 $.

it's why i want ask to you if i can use twenty micro sd card reader on a breadboard (with a power module, i presume) with my raspberry pi 2 :?:

xanthor
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Re: Storage server with RAID on multi micro sd cards

Tue Nov 03, 2015 4:36 pm

No, you can't buy a 512 GB memory card for $10. Such cards are fake and their real capacity is much lower. Buy a hard drive if you want to share a lot of data.

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Re: Storage server with RAID on multi micro sd cards

Tue Nov 03, 2015 4:57 pm

2TB hard drives are cheep - much cheeper than SDcards
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Re: Storage server with RAID on multi micro sd cards

Tue Nov 03, 2015 5:22 pm

omicrolibre wrote:i seen that we can found on ebay a 512 GB micro sd card at less than 10 $.
There is software that can change an sdcard or usb thumb drive to pretend it has most any amount of space. It really only has the amount that it has, at least trustably, apparently they are often bigger than they claim to be but there are tons of bad areas. You still might decide to use flash drives since they are quiet, not spinning, pretty portable. They aren't cheaper than hard drives though.
it's why i want ask to you if i can use twenty micro sd card reader on a breadboard (with a power module, i presume) with my raspberry pi 2 :?:
If you have a way to hook up a lot of drives, for example a USB hub and a handful of thumb drives, you can use LVM to decide how physical volumes are integrated into your logical volumes. So you could take 6 32gig flash drives and have one big drive that Linux sees.

fruitoftheloom
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Re: Storage server with RAID on multi micro sd cards

Tue Nov 03, 2015 6:07 pm

omicrolibre wrote:hi !

i want to create a storage sever with approximately a capacity of 8 or 10 To to share data with my friends by internet (i have more than 100 Mb/s upload connection). But i have not enough money to choose a hard drive solution, it's why i thinking about a RAID solution with micro sd cards since i seen that we can found on ebay a 512 GB micro sd card at less than 10 $.

it's why i want ask to you if i can use twenty micro sd card reader on a breadboard (with a power module, i presume) with my raspberry pi 2 :?:
Far better solution than SD Cards:

http://store.wdc.com/store/wdeu/en_GB/D ... iDrive_Kit
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blc
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Re: Storage server with RAID on multi micro sd cards

Fri Nov 06, 2015 9:53 am

The most reasonably priced SD cards you're probably going to find at the moment are 64GB; 2x64GB (£17 ea,, £34 total) is still cheaper than 1x128GB (£47 ea.). To achieve 8TB using 64GB SD cards you'll need 125 of them; using the ones linked above that's a total cost of £2,125.

Assuming you could build/assemble some kind of USB controller which can simultaneously read/write to 125 SD cards at full speed (which is the sort of engineering challenge that would land you any electronics engineering job in the world you could possibly want at whatever wage you choose) you'll still have problems with flash wear: flash memory cells will wear out far faster than a traditional hard drive. And, of course, it's not terribly cost-effective.

Alternatively you can get 3.5" hard drives rated for NAS use for £115 each. For the same price as two of those drives you'd only be able to get 832GB in SD card storage (13x 64GB SD cards). External SATA USB enclosures are relatively cheap, ~£10 to £20 at most, so you wouldn't have to build your own controller array.

More to the point though, I don't think the Pi is best suited for high-throughput NAS duties. The maximum throughput for USB2 is 480 megabits per second; the latest SATA version tops out at a maximum throughput of 6 gigabits per second. You're not going to get the benefit of the hard disk speed because you'll be limited by the USB bus on the Pi. You'll probably never achieve the maximum theoretical throughput because there will be all sorts of overheads which will impact the data transfer rate. On my home network I get a maximum transfer rate of about 100 megabytes per second (800 megabits per second) when transferring large files to my network server over gigabit ethernet; that's measured "real world" performance, not theoretical. I'm only using SATA 3Gb/s in my network server, and the real world performance is nearly twice as fast as what a USB2 port can theoretically achieve.

You'd be better off getting a dedicated NAS unit or building a network server out of cheap second-hand parts. For reference my network server is based on an Intel Core2Duo E5400 processor - relatively old hardware, and really cheap second-hand, but it still performs more than admirably.

omicrolibre
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Re: Storage server with RAID on multi micro sd cards

Fri Nov 06, 2015 8:05 pm

ok

i have buy a SD card, we never know maybe it's not a fake ... :roll: i will test it and i'll use the paypal garanty if it's not that i expected :D

for Hard Disk solution, i can't get enough money. i'll try again to make it in few years ...

thank you to all of you

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mikronauts
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Re: Storage server with RAID on multi micro sd cards

Fri Nov 06, 2015 8:22 pm

If you are VERY lucky, it might be a 64GB card, which is 512Gbit

The vendor will say... it IS 512Gbit!
omicrolibre wrote:ok

i have buy a SD card, we never know maybe it's not a fake ... :roll: i will test it and i'll use the paypal garanty if it's not that i expected :D

for Hard Disk solution, i can't get enough money. i'll try again to make it in few years ...

thank you to all of you
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