- my 4 year old 600gb (6x120gb) array is short of space! - I'm not entirely short of cash so I've been thunking lately !
So off I go trying to find the best bang-per-buck (or gig per quid) solution to my problem.... Idealy I need to at least double my space
so.. I take a look at the big list o' disks on the scan site. pasting them into a text file gives me something in this format (with a bit of cleanup, such as no review available, call for price, etc bollocks):
LN11540
250 Gb Samsung SP2514N SpinPoint P120, IDE (PATA), 7200 rpm, 8MB Cache, 8.9 ms £42.10 £49.47
Now you're asking, what use is that ? not much
Along comes a long, inefficient grep/sed/awk expression!
cat hdd-pricelist.txt | sed s/sterling//g | sed s/gb//gi | sed '$!N;s/\n/ /'| gawk '{ disksize = $2; disknumber = 8 ; spare = 1;raidsizemax = disksize * disknumber ; raidsizeeffective = ( raidsizemax - (spare * disksize ) ) ; raidprice = $NF * disknumber ; gigsperbuck = raidsizeeffective / raidprice ; print gigsperbuck" "raidsizeeffective" "raidprice" "$1};' | sort -n
the numbers I put in mean I want to build an 8 disk array with one drive spare - typicaly in raid5 you want 1 hotspare too, but raid5 can tollerate the loss of one disk, so I could buy more disks while running with limited performance ...
now, I haven't decided whether I want sata or pata or scsi, but purely on size/cost , I end up with the following table:
gigs per buck | effective raid size | price | code
4.20741 2100 499.12 LN15140
4.40229 1750 397.52 LN11461
4.41295 1750 396.56 LN12655
4.42187 1750 395.76 LN11540
Thats more like it! LN11540 yields spintpoints p120 250gb disk for a pata array and ln12655 returns (a maxtor diamondmax 250gb) the most effective sata disk. I haven't found any cheap PATA controllers for 8 port.... yet .. and sadly the only suitable SATA controller (the excellent pci-e rocketraid 2320) wallows in at almost 200 quid.
However a 5x300/320gb sata array may be more effective given that a revo 64 5 port is barely breaking 60 quid!
Yet to work out how good the lunix/bsd support is for the revo however, let alone whether the revo is even worth 60 quid - it looks dodgy.
But anyway, now to wire in some raid controller costs to the awk face off the revo 5 disk vs the rocketraid 8 disk options.
cat hdd-pricelist.txt blah blah |gawk '{ disksize = $2; controllercost = 52.88 ; disknumber = 5 ; spare = 1;raidsizemax = disksize * disknumber ; raidsizeeffective = ( raidsizemax - (spare * disksize ) ) ; raidprice = ( $NF * disknumber ) + controllercost ; gigsperbuck = raidsizeeffective / raidprice ; print gigsperbuck" "raidsizeeffective" "raidprice" "$1" revo5disk"};' > revo5disk.txt
cat hdd-pricelist.txt blah blah |gawk '{ disksize = $2; controllercost = 185.65 ; disknumber = 8 ; spare = 1;raidsizemax = disksize * disknumber ; raidsizeeffective = ( raidsizemax - (spare * disksize ) ) ; raidprice = ( $NF * disknumber ) + controllercost ; gigsperbuck = raidsizeeffective / raidprice ; print gigsperbuck" "raidsizeeffective" "raidprice" "$1" rocketraid8disk"};' > rocketraid8disk.txt
cat revo5disk.txt rocketraid8disk.txt | sort -n
so, sticking to satas..
3.00084 1750 583.17 LN11461 rocketraid8disk
3.00579 1750 582.21 LN12655 rocketraid8disk
3.00907 2100 697.89 LN14417 rocketraid8disk
3.03141 1000 329.88 LN12903 revo5disk
3.05642 1000 327.18 LN11544 revo5disk
3.05782 1000 327.03 LN5457 revo5disk
3.05826 1200 392.38 LN12595 revo5disk
3.06526 2240 730.77 LN14162 rocketraid8disk
3.06694 2240 730.37 LN14911 rocketraid8disk
3.07448 1280 416.33 LN13503 revo5disk
3.14436 1000 318.03 LN13120 revo5disk
3.15792 1280 405.33 LN13468 revo5disk
3.18441 1000 314.03 LN11035 revo5disk
3.2169 1200 373.03 LN14417 revo5disk
3.2522 1280 393.58 LN14162 revo5disk
3.25426 1280 393.33 LN14911 revo5disk
3.31862 1000 301.33 LN11461 revo5disk
3.32524 1000 300.73 LN12655 revo5disk