On Wed, Oct 12, 2016 at 11:18:40AM +1100, russell@coker.com.au wrote:
On Wednesday, 12 October 2016 1:31:33 AM AEDT Craig Sanders via luv-main wrote:
the only time i've ever seen something similar was my own stupid fault, i rebooted and just pulled out the old SSD forgetting that I had ZIL and L2ARC for the pools on that SSD. I had to plug the old SSD back in before I could import the pool, so i could remove them from the pool (and add partitions from my shiny new SSDs to replace them).
Did you have to run "zfs import" on it or was it recognised automatically? If the former how did you do it?
after plugging the old SSD back in? can't remember for sure, but i think so....it wasn't imported before i rebooted again so wouldn't have been automatically imported after reboot. I probably did something like: zpool import -d /dev/disk/by-id/ <poolname>
Is the initramfs configured to be able to run zfs import?
yes, i have zfs-initramfs installed.
BTRFS snapshots are working well on the root filesystems of many systems I run. The only systems I run without BTRFS as root are systems where getting console access in the event of problems is too difficult.
yes, but you can't pipe `btrfs send` to `zfs recv` and expect to get anything useful. my backup pool is zfs. and so far, i've had 100% success rate (2/2) with zfs rootfs. Disclaimer: not a statistically significant sample size. contents may settle during transport. void where prohibited by law. serving suggestion only. batteries not included.
crucial mx300 275G SSDs(*). slightly more expensive than a pair of 500-ish GB but much better performance....read speeds roughly 4 x SATA SSD read (approximating pci-e SSD speeds), write speeds about 2 x SATA SSD.
i haven't run bonnie++ on it yet. it's on my todo list.
If you had 2*NVMe devices it would probably give better performance than 4*SATA and might be cheaper. That would also leave more SATA slots free.
yes, that would certainly be a LOT faster. can't see any way it could be cheaper. i'd have to get a more expensive brand of ssd plus i'd need an nvme pci-e card or two. However, I have SATA ports in abundance. On the motherboard, I have 6 x SATA III (4 used for the new SSDs, two previously used for the old SSDs but now spare) plus another 2 x 1.5Gbs SATA, and some e-sata which i've never used. In PCI-e slots, I have 16 x SAS/SATA3 on two IBM 1015 LSI cards (8 ports in use, 4 spare and connected to hot-swap bays, 4 spare and unconnected). PCI-e slots are in very short supply. and my m/b doesn't have any nvme sockets. If I could find a reasonably priced PCI-e 8x NVMe card that actuAlly supported two PCI-e NVMe drives (instead of 1 x pci-e nvme + 1 x sata nvme), i'd probably have swapped out the spare/unused M1015 cards for it. i don't have any spare 4x slots. so i did what I could to maximise performance with the hardware I have. everything I do on the machine is noticably faster, including compiles and docker builds etc. but yeah, eventually I'll move to PCI-e NVME drives. sometime after my next motherboard & cpu upgrade. I'm waiting to see real-world reviews and benchmarks on the upcoming AMD Zen CPU. Intel has some very nice (and expensive) high-end CPUs, but their low-end and mid-range CPUs are more expensive than old AMD CPUs without offering much improvement....might make sense for a new system, but not as an upgrade. Every time I look into switching to Intel, it turns out I'll have to spend around $1000 to get roughly similar performance to what I have now with a 6 year old AMD CPU. I'm not going to spend that kind of money without a really significant benefit. I could get an AMD FX-8320 or FX-8350 CPU for under $250 but I'd rather wait for Zen and get a new motherboard with PCI-e 3.0 and other new stuff too. Just going on past history, I'm quite confident that will be significantly cheaper and better than switching to Intel...i expect around $400-$500 rather than $800-$1000.
we're just on the leading edge of some massive drops in price/GB. a bit earlier than I was predicting, i though we'd start seeing it next year. wont be long before 2 or 4TB SSDs are affordable for home users (you can get 2TB SSDs for around $800 now). and then I can replace some of my HDD pools.
It's really changing things. For most users 2TB is more than enough storage even for torrenting movies.
btw, for torrenting on ZFS, you need to create a separate dataset with recordsize=16K (instead of the default 128K) to avoid COW fragmentation. configure deluge or whatever to download to that and then move the finished torrent to another filesystem. probably same or similar for btrfs.
I think that spinning media is going to be mostly obsolete for home use soon.
yep. and good riddance. i'd still want to buy them in pairs, for RAID-1/RAID-10 (actually, ZFS mirrored pairs)
i'll read through that (and the fedora one that it links to) before rebooting my myth box with systemd again. it was an unintentional reboot anyway. i'd used grub-set-default intending to reboot to systemd next time, but the thunderstorm caused a few second power-outage and the UPS for that machine died ages ago (haven't replaced it yet). was busy with other stuff and didn't even notice it was down for a few hours.
From a quick read of the man page it appears that the -D option to journalctl might do what we want. It appears that Debian has moved to not having the binary journals so I don't have a conveniant source of test data.
looks like Storage=auto in /etc/systemd/journald.conf, but /var/log/journal isn't created by default. so no persistent journal by default. bad default. debian configuring it to use rsyslogd by default is a good thing, but doesn't help when the system won't boot far enough to get rsyslogd running. should be on by default. maybe even automatically turn off journald's persistence as soon as rsyslogd (or whatever external logger) successfully starts up. craig -- craig sanders <cas@taz.net.au>