Hard Drive space

[JPC-Larry]

How much total hard drive space do you have lying around these days combined? I have very little stored so I actually only have about 500 gigs available to me.

To think, back in the day I'd say nobody will need a terabyte and now it's becoming relatively common to have a TB or more.

[Ron]

I just saw a terabyte external USB 2.0 hard drive (of course with one button backup) for $120 including shipping.

For an extra $10, you can go to a 1TB USB 2.0 OR eSATA box.

USB 2.0 is 60MB/sec, eSATA is 300MB/sec.

Theoretically, of course.

[JPC-Larry]

Amazing, I remember when it cost roughly 300 bucks for an 80 gig.

[Ron]

Ya well, the first 5 MEGAbyte "Winchester" drives were $5,000 too.
I had a nifty Priam drive that was about 60MB and parked itself with a "CLUNK!" on power off/failure and rattled like a baby's toy but it was a screamer for it's day (1986)

Disk space amazes me, but not more so than flash memory. 32GB in just a tiny little SDHC package, and it is non-volatile! I remember in Star Trek they held up a something (a crystal? a cube?) and said it was all of the knowledge of some civilization... taken from another ship. Perhaps they even said "terabytes" I am not sure. sigh.

We talked about disk drives once before and I published my photo (post #14) here in this thread:
Forums Speed

3 years ago the price for the 1TB external drive was... $700!!

[Pawel Kowalski]

I'm sort of a hard drive collector since I am always running past my capacity and I'm too broke at times to spend money on a large drive. Currently my desktop has the following hard drives in it:

1 500Gb
1 80GB
1 120GB
1 external 120GB

then I have a server I use for multimedia and backups and testing which has the following:

1 80GB
1 320GB

the 320GB is brand new so I have a few months before I fill it up .

I do remember my first computer my dad got me in the 90s that really got me in to computer hardware since I got to tear this thing up. It was a ultra fast 486 with a huge 320Mb hard drive running windows 95.

[JPC-Tracie]

I have a 350 GB HD that I'm nowhere close to filling. But my husband stores all our MP3's, photos, etc on a server. Trying to come up with how many hard drives and space we have combined in this household would hurt my head. (My husband hoards computer parts...)

[JPC-NickO]

Hi,

Doing a total combined amount of available hard drive space is a little hard for me since most of my disks are in RAID arrays.

Workstation:
2x 250GB RAID 1 Mirroring.
Total space 500GB, usable space 250GB
This just stores my application install and OS install... nothing important on here.

File Server:
3x 500GB RAID 5
1x 80gb system disk
Total storage 1580GB, Usable storage 1080GB. Around 85% used, need a few more drives :P

General Server (NAT, firewall, DHCP, IPv6 tunnel)
1x 320GB
1x 120GB
Total storage: 440Gb, usable 440Gb

Also have a 250GB hard drive on RMA.

[Ron]

Do you have a controller (or software) that can handle adding an additional drive to your RAID 5 array to increase storage? I'd imagine it would have to rebuild the entire array's data to spread it across?

[JPC-NickO]

Hi Ron,

I'm using a cheap Promise TX4 4 port SATA II PCI controller card for the raid array. I'm using Linux software raid because I'm cheap and it's more flexible.

If/When I extend it I'll slap in another cheap controller card and build a new raid device on the new volume and just extend the LVM partition that currently has my data on it and then grow the file-system to fill the new volume.

You can just add a extra disk and and just rebuild the array. I did that originally when I first setup raid. I had a single 500gb hard disk with my data on it and just bought two new 500gb hard drives and created the raid array with the 3rd disk missing. rsync'ed all the data from the first drive to the raid volume and then added the original disk as the 3rd disk in the raid array.

I was actually thinking about buying another system and setting them both to mirror each other with fail-over. (Yes, this is excessive for a home network but I like to play.)

[Ron]

I see you did that from no RAID to new RAID, but can you do it with full drives already in RAID 5? I'd think you'd sort of have to perform a defragment-style move of data from the 3 drive volume to the 4 drive volume... but I'm not familiar with current tech and wasn't that familiar with the older stuff, either.

I seem to think it could have been done with Veritas software... I recall making all sorts of logical volumes within physical drives, but with full volumes?...

Your approach will "waste" another parity drive, no?

[JPC-NickO]

Hi Ron,

Raid 5 is a striped set with distributed parity this means that the extra space it will take up is only drive_size(number_of_drives-1).

If I just wanted to add a single 500gb disk to the array (extending it from 1tb to 1.5gb)
I would add the disk to the computer and then boot it up.

then to add it to the array (md0) as spare drive
mdadm --add /dev/md0 /dev/sdd1

now to have grow the array so I can use the extra space
mdadm --grow /dev/md0 --raid-devices=4

the software raid will now reshape the array... it will take few hours.
watch -n1 'cat /proc/mdstat'

now the md0 will have an extra 500gb that isn't partitioned

before resizing the file-system I need to take it offline
umount /dev/md0

now I need to re-size the file-system to use the whole array.

resize_reiserfs /dev/md0

after that mount it back up and it's got 500gb more space.
mount /dev/md0

Naturally, you would not do it this way without having backups available to restore from.

[Ron]

I thought your stated approach was to set up another RAID 5 array, thereby wasting that new parity drive. Did I misunderstand that?

Cool beans about adding a new drive to the array and letting the software "reshape" the data. Sounds like a fun process to watch... like defragmenting a huge drive.

[JPC-NickO]

I thought your stated approach was to set up another RAID 5 array, thereby wasting that new parity drive. Did I misunderstand that?

Cool beans about adding a new drive to the array and letting the software "reshape" the data. Sounds like a fun process to watch... like defragmenting a huge drive.

Ah, I wasn't sure which method you were referring to.

If/When I extend it I'll slap in another cheap controller card and build a new raid device on the new volume and just extend the LVM partition that currently has my data on it and then grow the file-system to fill the new volume.

Doing it this way does require another 500gb reserved for parity data but it also allows me to read and write the data a bit faster and is more reliable than having 6 drives in a RAID 5 array.

In the event of a disk failure it would also reduce the time it takes for the raid array to rebuild because it is smaller. (2x 1.5TB arrays vs 1x3TB array)

More complicated and slightly more expensive per Gb but I think the advantages outweigh the cost.

[Ron]

Just wondering:

Wouldn't it be 5 drives in the original array vs. 6 drives in two arrays for the same 2TB logical capacity? Plus one controller vs. 2?
Does adding a 6th drive decrease your MTBF by 20%?
Does an extra RAID array double the likelihood of controller failure?
Don't forget electricity!

While you may have a penalty for extra drives in RAID 5 for writing (and I'm not sure about that), don't you have a gain in read speed? Don't all the heads position asynchronously (at least on reads)?

Fun stuff!

[the_ancient]

Primary PC: 250Gb
HTPC: 790GB
NAS: 1000GB
Linux Server: 100GB

Total Storage Cap: 2.1 Terrabytes

That is my Home network, Probably double that if I VPN to my office