1 |
On 15 Mar 2010, at 16:26, Steve wrote: |
2 |
> ... |
3 |
> From ages ago, I remember iSCSI being bandied about. Did that ever go |
4 |
> anywhere (i.e. is this easy to do from Gentoo?) |
5 |
|
6 |
I believe it is quite widely used - it is mentioned often on the linux- |
7 |
poweredge list. I would imagine the Linux kernel allows mounting and |
8 |
sharing by iSCSI - check `make menuconfig` and type "/iscsi". |
9 |
|
10 |
It's hard to be more specific without knowing your usage. |
11 |
|
12 |
For storage of a "mere terabyte" you can buy a networked storage |
13 |
enclosure which will accommodate two drives. These are cheap, do |
14 |
mirroring, will accommodate standard 1TB, 1.5TB, 2TB drives, but are |
15 |
probably not too fast. |
16 |
|
17 |
One reads a lot posted by people who have large movie collections |
18 |
stored on the network, whether they be MythTV users or the mutineer |
19 |
sailors of 17th century galleons. A PC-based solution gives you more |
20 |
room for this - you can fit perhaps 4 drives in a standard PC case you |
21 |
find at the tip, or you can get 12 or 16 drives in a dedicated |
22 |
rackmount server case. This allows capacity of upto 32TB with current |
23 |
drives, if you can afford that, or to use cheaper drives (1TB or 1.5TB |
24 |
are best gigabytes-per-dollar at present, I think; 500gb drives seem |
25 |
recently to have become disproportionately expensive) and have better |
26 |
RAID levels. |
27 |
|
28 |
The Norco one is popular amongst enthusiasts, because it's really |
29 |
cheap [1]; it uses 2 x standard ATX power supplies, one for the |
30 |
mainboard, one for the drives. You can get similar cases with the |
31 |
option of hot-swap PSUs - Chenbro used to be the main brand for this, |
32 |
I think, but in the last couple of years TST <http://TSTcom.com> have |
33 |
started producing nicer cases; I use a TST ESR-316, which is utterly |
34 |
lush, but which was expensive. I have one slight reservation about the |
35 |
TST, which I will not spend time detailing unless you ask. |
36 |
|
37 |
I use only half the TST's capacity at present, but it is a pleasure |
38 |
and a relief to have so much room available; expansion of network |
39 |
drive capacity is never a problem - just slap a drive in and you're |
40 |
ready to go. Even with as many as 6 or 8 drive bays there are corner |
41 |
cases which can make expansion a bit of a headache (at least if uptime |
42 |
is important). |
43 |
|
44 |
Since these cases accommodate standard ATX motherboards, you get to |
45 |
use an old Pentium 4 motherboard salvaged from an old PC or an Atom- |
46 |
based motherboard for £100 or so. The latter price is a bit shocking, |
47 |
IMO, compared to (say) the Asus EE-PC, but it reflects the demand for |
48 |
them; they're prolly only $100 in the US. These atom motherboards have |
49 |
minimal expansion slots, but if you only want to use it for storage |
50 |
then you're probably fine with just one. |
51 |
|
52 |
If you build your own server you can use software or hardware RAID. |
53 |
Fast hardware RAID, based on an PCIe controller card, is expensive. |
54 |
You can get PCI or PCI-X hardware RAID very cheaply on eBay these |
55 |
days, but it's slow. That is to say that PCI or PCI-X hardware RAID is |
56 |
fast enough to stream a couple of movies at the same time, fast enough |
57 |
to copy 5gb files only a couple of minutes, but production server |
58 |
systems (if you were buying a database server for work) would be |
59 |
expected to use a PCIe-based hard-drive controller. Hardware RAID is |
60 |
nice in its ability to hot-swap out a failed hard-drive without |
61 |
interruption. I have not found non-RAID SATA controllers that satisfy |
62 |
me with their ability to do hot-swap (although I would love to). |
63 |
|
64 |
Managing RAID on a PC-based server - rather than a dedicated NAS |
65 |
enclosure - very easily allows expansion. With RAID5 or 6 you can just |
66 |
add in another drive and expand on to it. I use an old PCI-X (fits in |
67 |
a PCI slot) 3ware 9500 card, and it *seems* like if you have a RAID1 |
68 |
(haven't tried RAID5) on two drives of capacity X, then remove each of |
69 |
those drives in turn, rebuilding onto drives of X+Y capacity, then |
70 |
upon completion the array appears to the o/s as the larger X+Y size. I |
71 |
think some LSI cards do this, also. I would not bet on the ability of |
72 |
low-end NAS boxes to do this. |
73 |
|
74 |
A company called Drobo makes some high-end NAS hardware with space for |
75 |
plenty of drives (on some models) and some fancy features. I find UK |
76 |
prices a bit shocking, but depending upon your application they might |
77 |
be justified; the US prices seem quite reasonable to me. |
78 |
|
79 |
I wouldn't get too het up about Samba / CIFS vs NFS. Samba / CIFS can |
80 |
be faster than NFS, even in an all-Linux environment. Other times it's |
81 |
not. This seems pretty much random, depending upon whom is doing the |
82 |
benchmarking. On an intellectual level, at least, I find neither |
83 |
wholly satisfying - it would be really nice to have a Linux-native |
84 |
network filesystem that does authentication / permissions properly. |
85 |
But both do work. |
86 |
|
87 |
I looked at ZFS, but decided that Solaris, from a look at the HCL, was |
88 |
too picky over hardware. I think ZFS is great, I no longer think it's |
89 |
the future. My selection of cheap hardware is far wider under Linux, I |
90 |
can install Gentoo and just `emerge mediatomb` and stream movies to my |
91 |
PS3. |
92 |
|
93 |
So there ya go. Lots of options, budget from dead cheap to mega money. |
94 |
Depends how much you can justify. |
95 |
|
96 |
Stroller. |
97 |
|
98 |
|
99 |
|
100 |
[1] http://www.newegg.com/product/product.aspx?item=n82e16811219021 |