| 1 |
Florian D. posted <4368B219.1070903@×××.at>, excerpted below, on Wed, 02 |
| 2 |
Nov 2005 13:33:29 +0100: |
| 3 |
|
| 4 |
>> ... As some may guess, I've been studying this stuff recently! =8^) I |
| 5 |
>> don't have my own RAID setup yet, but probably will by late this week. (I |
| 6 |
>> plan to go pickup the drives probably Tue or Wed.) |
| 7 |
> good luck. when there is no email from you for some days, then we know |
| 8 |
> sth. went wrong ;-) |
| 9 |
|
| 10 |
=8^) I have the drives... four Seagate SATA 300 gigs. I got them |
| 11 |
yesterday and installed them this AM. I haven't done anything with them |
| 12 |
yet, so they're just empty unconfigured drives still, but the BIOS and |
| 13 |
kernel see them, so I've gotten a good start! =8^) |
| 14 |
|
| 15 |
I've now got this full tower case stuffed to the gills! =8^) The four |
| 16 |
SATA drives, my current main drive, a 250 gig Maxtor PATA, on PATA primary |
| 17 |
master, a DVD writer on PATA primary slave, an old 36 gig Maxtor on PATA |
| 18 |
secondary master, and a CD writer on PATA secondary slave. Round that out |
| 19 |
with a legacy 3.5" floppy, and I've got 9 drives in this thing, with > 1.4 |
| 20 |
TB of hard drive capacity (pre-raid mirror/parity discounting)! |
| 21 |
|
| 22 |
The 250 gig still has ~100 gig not even formatted yet, but my AC went out |
| 23 |
this summer and it got hot and developed some bad blocks. With them all |
| 24 |
marked and one 4 gig partition written off entirely, it has proved |
| 25 |
decently stable, but I've been worried about it, thus the current upgrade |
| 26 |
job. I've been considering RAID and drives are now cheap enough to do it, |
| 27 |
so I decided to go for it! |
| 28 |
|
| 29 |
I'll be setting up three RAID sets on the four SATAs, and will be using |
| 30 |
the Maxtors as emergency boot and backups. A small 4-way raid1 will have |
| 31 |
/boot. The majority of the disks, 200+ gig of each of the four, will be a |
| 32 |
raid6 (raid5 but with two parity copies... any two drives can go down, one |
| 33 |
out is supposed to maintain speed fairly well, two out will drop speed |
| 34 |
substantially but will still function) carrying root, /usr, /var, /home, |
| 35 |
and my dedicated mail, news, and media LVs. A medium size raid0 |
| 36 |
will complete the roundup, containing /tmp (which is $PORTAGE_TMPDIR) and |
| 37 |
a dedicated ccache LV. I'm currently running 1G memory and no swap, but |
| 38 |
I think I'll reactivate swap as well while I'm at it, with a small |
| 39 |
non-raid swap partition on each of the four. The kernel stripes swap on |
| 40 |
its own, so there's little reason for me to put it on raid, and one of |
| 41 |
the reasons I'm reactivating swap is to try out the developing kernel SMP |
| 42 |
suspend features. =8^) Having swap on raid isn't likely to work too well, |
| 43 |
when I'm trying to load memory images out of swap coming out of suspend! |
| 44 |
|
| 45 |
I'll use my existing Maxtor PATAs, as I said, for an emergency boot |
| 46 |
installation and off-RAID online backups, and plan on using LVM2's |
| 47 |
snapshotting capacities to maintain probably up to two working snapshots |
| 48 |
(yes, I'm aware of the write penalty of doing so) of root and /usr, taken |
| 49 |
before any major upgrades, such as to a new baselayout or a new version of |
| 50 |
KDE. Once I verify functionality of the new upgrades, I'll make |
| 51 |
necessary config changes (like switching fstabs), then write off the |
| 52 |
snapshot to the non-raid emergency backup, so I can remove it and avoid |
| 53 |
the write penalty of the COW (copy on write) snapshot. |
| 54 |
|
| 55 |
Currently, I have a working copy and a backup copy of both root and /usr |
| 56 |
on each of my Maxtors, therefore, four OS area snapshots total. That has |
| 57 |
proven to be a good strategy, when I got those badblocks due to the bad |
| 58 |
A/C and consequent overheating, but after having used it, I decided it |
| 59 |
needed a bit of modification, mainly in that I needed a better way to keep |
| 60 |
the snapshots updated so they didn't get massively outdated. The RAID |
| 61 |
gives me better reliability on the one side (and the Seagates with their 5 |
| 62 |
year warrantee are nice in that department as well), and lvm2's |
| 63 |
snapshotting should come in handy as an intermediate stage from the other |
| 64 |
angle. |
| 65 |
|
| 66 |
As I mentioned, I still have ~100 gig unpartitioned on the 250 gig. I'll |
| 67 |
maintain that practice on the raid, but the dynamic expansion capabilities |
| 68 |
of lvm2 will provide significant additional flexibility in that area. |
| 69 |
|
| 70 |
Well, I've got a quite a bit of work to do still, soo... |
| 71 |
|
| 72 |
-- |
| 73 |
Duncan - List replies preferred. No HTML msgs. |
| 74 |
"Every nonfree program has a lord, a master -- |
| 75 |
and if you use the program, he is your master." Richard Stallman in |
| 76 |
http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html |
| 77 |
|
| 78 |
|
| 79 |
-- |
| 80 |
gentoo-amd64@g.o mailing list |
Archives