Raspberry Pi Forums

Posted: **Sat Jun 04, 2016 9:18 pm**

I have a bunch of old hard drives which consist of SCSI hard drives, ATA hard drives and SATA hard drives. I was just wondering if it possible to combine then and to make one big hard drive? I assume not because there different rpms and different ports but is there anyway i can somehow put them to use for a home cloud?
Thankyou.

Posted: **Sun Jun 05, 2016 2:06 am**

mnai wrote:I have a bunch of old hard drives which consist of SCSI hard drives, ATA hard drives and SATA hard drives. I was just wondering if it possible to combine then and to make one big hard drive? I assume not because there different rpms and different ports but is there anyway i can somehow put them to use for a home cloud?
Thankyou.

You would need a USB adapter AND power supply for each drive.
USB to SCSI adapters are very very expensive. Well over $100 US even from China.
USB to SATA or IDE adapters are fairly cheap. I have a combo that can do either IDE or SATA (Not both at the same time however).
However even 1 modern xTB SATA drive can take the place of a 'bucket full' of older drives.
FYI many 2.5" drives can be used on a RPi powered directly from the USB adapter so no external power supply needed.

Posted: **Sun Jun 05, 2016 8:48 am**

It sounds like you want to use LVM2 (Logical Volume Manager), where you create LVM partitions on each drive, add them to LVM as Physical Volumes. Join them together into a Volume Group, then create Logical Volume(s) in the group, and create filesystems on the result.

Code: Select all

pi@raspi3 ~ $ apt-cache show lvm2
Package: lvm2
Version: 2.02.111-2.2
Architecture: armhf
Maintainer: Debian LVM Team <pkg-lvm-maintainers@lists.alioth.debian.org>
Installed-Size: 1520
Depends: libc6 (>= 2.15), libdevmapper-event1.02.1 (>= 2:1.02.74), libdevmapper1.02.1 (>= 2:1.02.90), libreadline5 (>= 5.2), libudev1 (>= 183), init-system-helpers (>= 1.18~), lsb-base, dmsetup (>> 2:1.02.47), dmeventd (>> 2:1.02.90), initscripts (>= 2.88dsf-13.3)
...
Description: Linux Logical Volume Manager
 This is LVM2, the rewrite of The Linux Logical Volume Manager.  LVM
 supports enterprise level volume management of disk and disk subsystems
 by grouping arbitrary disks into volume groups. The total capacity of
 volume groups can be allocated to logical volumes, which are accessed as
 regular block devices.

There are some (slightly outdated and over complicated) instructions here http://tldp.org/HOWTO/LVM-HOWTO/index.html
The "Common Tasks" section http://tldp.org/HOWTO/LVM-HOWTO/commontask.html covers most of what you need.

Once you've got the hang of the concepts it is fairly easy to use and very flexible. You can resize filesystems, add and remove disks and all sorts of things.

Recently I had a disk that was showing signs of failing (very high recoverable read error rate), so I added a new disk into the VG and moved the contents of the bad disk onto the new one whilst it was in use.

Posted: **Sun Jun 05, 2016 12:10 pm**

Big laptop USB drives are quite inexpensive.
USB 2 is not a good data transfer bus.
Connecting a bunch of old drives will cost you and you won't get the performance and reliability of a single modern HDD.
Recycle those drives or put them to use in a computer that at least offers SATA.

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Combining old hard drives to make one big cloud.

Combining old hard drives to make one big cloud.

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