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