fastest way to shut down the OS

[sithlord48]

Re: fastest way to shut down the OS

Of course, IF the necessity to just down your system is REALLY urgent one can throw the power switch and rely on the power of EXT4 journaling to restore the system at the next boot up. Running beta OSs and software one has the occasional necessity, when magic keys don't work, to pull the plug in order to regain control EXT4 has never failed to restore my file system without data loss.

yea i have not had ne file lost from ext4 either.. and i have "pulled the plug" quite a few times.. and i was all worried about ext4's recovery features. (then again it was beta back then)

[GreyGeek]

Re: fastest way to shut down the OS

I was too, for a while.

It's not that journals are supposed to restore file systems to their prior state, it was just that EXT4 was new back then and like any software it had to be shaken out before one could rely on it. Now, I believe that EXT4 is very reliable. Like I said, since I began using it over a year ago I have never had a fs failure, or lost data. BUT, I must add, I had the automatic file check that takes place every so often. ReiserFS v3 never had to do that and I found it equally reliable.

[sithlord48]

Re: fastest way to shut down the OS

as some of you may have heard the in the northeast (where i live) lots of power outages from storms lately, my server has not lost 1 bit of data and its this week had its power suddenly cut several time (think its time to go buy a UPS...) all my disks are ext4. the autocheck feature is a good idea... keeps my disks ready to work all the time. and the speed boost ext4 gives to that check is amazing.

[GS2]

Re: fastest way to shut down the OS

Create shell script, set to executable and run it.

[gemmakaru]

Re: fastest way to shut down the OS

I press the power button and it shows a shutdown dialog, enter chooses the default switch off. Pretty fast.

[sithlord48]

Re: fastest way to shut down the OS

I press the power button and it shows a shutdown dialog, enter chooses the default switch off. Pretty fast.

i never press my power button to shutdown i use a command or the gui the only time i touch that button is when its locked up and has to be manually haulted (when alt+sysrq R-S-E-I-U-B fails)

[lmilano]

Re: fastest way to shut down the OS

Yes, it's best to avoid power down, and only do it as a last resource. Not everyone has been lucky with ext4:

http://www.phoronix.com/scan.php?pag...item&px=Nzk0OA

I still think it's the best FS around in terms of overall performance and safety, but hey, life happens.

[gemmakaru]

Re: fastest way to shut down the OS

Just to be clear the power button shows the same shutdown dialog as the desktop menus. It doesn't just kill the power. I'm not talking about the main switch hehee.

[sithlord48]

Re: fastest way to shut down the OS

Just to be clear the power button shows the same shutdown dialog as the desktop menus. It doesn't just kill the power. I'm not talking about the main switch hehee.

normal for ACPI machies, you can change that behavor. but if you want to power it off u have to hold the button for 4 seconds (or change it in ur bios)

[Troberg]

Re: fastest way to shut down the OS

There's a plasmoid which you can use to place a shutdown button and logout button on a panel. Just click it and you're out.

[GreyGeek]

Re: fastest way to shut down the OS

Yes, it's best to avoid power down, and only do it as a last resource. Not everyone has been lucky with ext4:
http://www.phoronix.com/scan.php?pag...item&px=Nzk0OA
I still think it's the best FS around in terms of overall performance and safety, but hey, life happens.

About a year ago there was a big dust-up about the EXT4 cache write back:

Krogh reported a significant delay when writing from cache with the ext3 filesystem, despite faster hardware and extensive RAM. Was there a way to autotune it? Ingo Molnar opined that Krogh's wait time of 10 minutes was totally unacceptable, "it is the year 2009, not 1959." His personal "pain threshold" is about one second: "the historic limit for the hung tasks check was 10 seconds, then 60 seconds."
...
Synchronization in ext3 occurs every five seconds, whereas ext4 normally writes from cache every two minutes.
...
In his response, Ts'o fell back on the performance benefits thanks to delayed allocation, as had been allowed earlier under POSIX. By his experience, the difference between five seconds and three minutes "wasn't that big of a deal" in practice, "at least in the days when people were proud of their Linux systems having 2-3 year uptimes." Plus there was a remedy: "For precious files, applications that use fsync() will be safe." If this were a problem for some, they could "turn off delayed allocation with the nodelalloc mount option."

Torvolds replied:

Kernel chief Torvalds is hardly convinced by these arguments. In his view, "if you write your metadata earlier (say, every 5 sec) and the real data later (say, every 30 sec), you're actually more likely to see corrupt files than if you try to write them together... This is why I absolutely detest the idiotic ext3 writeback behavior. It literally does everything the wrong way around -- writing data later than the metadata that points to it. Whoever came up with that solution was a moron. No ifs, buts, or maybes about it."

So, it's the old battle about performance versus reliability. It depends on what you are doing at the time. If you are just browsing, or playing games, or doing anything else which doesn't save important data, having "data=writeback" in fstab will give you improved fs performance. If you are constantly writing documents, programming, running client front ends to important back end databases, etc..., then you want reliability. Mounting your HD with "nodelalloc" will bring it.

So, if you have a sudden power outage, or require an abnormal end (abend) then the issue of data loss depends entirely on your configuration of EXT4. I use the default settings and since I've been using Kubuntu I've never had data loss, despite having to power cycle. (Power interruptions never bother me because a laptop's battery is like an UPS)