newkomer to linux, new custom pc, need help/suggestions (long)

[darbotic]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Dibl: That's exactly the math I needed. For some reason I couldn't quite understand how to compute the cylinder/GB equation but you laid it out for me in an easy to read idiot's guide. :P thanks for that. I understood about how to add more than one partition, I just didn't know how many cylinders I needed to add together. Indeed, I am only practicing my fdisk skills, as you can see, which are in dire need of practice. I'll be trying again tonight after I get off of work.

[dibl]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Excellent.

Truth be told, it's the type of thing that you can get good at for 15 minutes when you need to, then 6 months later you find you have lost it all.

It happens that I've set up 3 different SSDs to boot and run Linux in the past 6 weeks. So I haven't quite forgotten it, just yet.

[oshunluvr]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

it's the type of thing that you can get good at for 15 minutes when you need to, then 6 months later you find you have lost it all.

which is why I keep a text file on my desktop called "tips". I cut-n-paste little tidbits of info like this one into it. 8)

Memory loss is one of three things I hate about getting older....

<wait for it>

... I forget the other two.


Here's some more tips for SSD's and linux http://tombuntu.com/index.php/2008/0...-state-drives/

[dibl]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Nice link oshunluvr -- thanks!

That's the second place I've seen recommending a different I/O scheduler for SSDs. That's the one thing I have not implemented - maybe I should give the deadline scheduler a try, and see if it makes any difference.

I also save copies of my /etc/fstab and /etc/sysctl.conf files in a place where I can get to them when configuring a new system - saves a lot of research time to re-learn what I once knew.

That article didn't mention the virtual memory "vm" performance tweaks for /etc/sysctl.conf, most of which are equally applicable to hdds and ssds. Here's the customized part of /etc/sysctl.conf file on the SSD-based desktop system I'm using at the moment (note this is a desktop system on a UPS -- this is not a generic recommendation):

.
.
.
# Log Martian Packets                                                               
#net.ipv4.conf.all.log_martians = 1                                                        
#
vm.swappiness=1
#
vm.vfs_cache_pressure=25
#
vm.dirty_writeback_centisecs = 30000
vm.dirty_expire_centisecs = 30000
vm.dirty_ratio = 50
vm.dirty_background_ratio = 2
#

Sources:

http://rudd-o.com/en/linux-and-free-...ow-to-fix-that

http://www.cyrius.com/debian/nslu2/linux-on-flash.html

http://www.westnet.com/~gsmith/conte...ux-pdflush.htm

http://people.redhat.com/nhorman/papers/rhel4_vm.pdf

http://www.enterprisenetworkingplane...Management.htm

http://www.lesswatts.org/tips/disks.php

[MoonRise]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

GParted will happily partition your SSD any way you want. And Windows will (so I am told) automatically account for alignment of the beginning partition to the beginning of the first available erase block. But GParted doesn't know about SSD erase blocks, and if you don't attend to the alignment manually, you'll be erasing (overwriting) your SSD exactly twice as much as necessary, thereby cutting its life expectancy in half, as well as slowing performance.

Here's some background: http://www.ocztechnologyforum.com/fo...e-working-life.

Interesting. I've entertained the notion of a SSD but didn't know about that. Thanks!

Edit: I'll have to admit that as long as I've been doing this type of work I've never heard of Partition Alignment. I'll have to look further into that for everything.

[Snowhog]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

I'll have to look further into that for everything.

If I read dibl's comment correctly, 'alignment' is only an issue on SSDs. Non-SSDs aren't affected.

[MoonRise]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Actually it is also useful with RAID set-ups and truthfully I can see where that would be an issue. I've already read so many articles on this that it is a very interesting issue. At least to me which probably shows what a Geek I am. Oh well. Geek it be.

[oshunluvr]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Also : To enable trim you need a 2.6.33+ kernel (this may not apply if your SSD has built in trim support via it's internal controller).

And you shouldn't use SSD's in a RAID without internally supported trim (software trim doesn't see through the raid device).

[dibl]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

(software trim doesn't see through the raid device).

True, until very recent times. However, see this: http://www.ocztechnologyforum.com/fo...pport-on-Linux

[oshunluvr]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Another good page to bookmark - Thanks!

[darbotic]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Ok just wanted to give an update. I finally got my hard disk partitioned and aligned. I was able to do it using TortureTest's guide by aligning the cylinders. Out of curiosity, any idea as to why it wouldn't work trying to align by sectors? I partitioned 4 total partitions as follows: 10GB for boot, 10GB for root, 2GB swap, and the rest (~15GB) as /home. Wrote those to disk and rebooted to verify alignment. I tried to look up some info regarding portprobe but didn't look into it very much so decided not to use it. After verifying the partitions were aligned I proceeded to install kubuntu 10.10 and chose to manually install onto the partitions that I had created. Success!!

One thing, though, which I'll look into more as I find time, is to edit my GRUB2 info. When the computer boots up I get way too many options to boot to. I have Kubuntu, Kubuntu Restore, 2 more Kubuntu's, 2 memory tests, Windows, and Windows restore. What I did was unplug my windows hdd while I was messing with this other hdd formatting and whatnot. After the install I plugged the Windows hdd back in and loaded Kubuntu, then did a grub-update in fdisk and mentioned above is everything it found.

I just wanted to let you guys know, though, I was successful on aligning and partitioning the disk. Now I'll have to do a little more research and mess with the 'noatime' and journaling of the ext4 so I'll know how to set it up if I decide to go with the ssd. Thank you so much for everyone's information, suggestions, and points of view. Though at times I may disagree with certain points I am in no way discounting any information from people who have been using this system longer than I have been, and I appreciate the patience and understanding. I'll be reading lots of information, I'm sure, here on the boards to improve my knowledge. Thanks again!

[dibl]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Sounds right. I think the "sectors vs. cylinders" thing is a "distinction without a difference", in this case. fdisk is looking for cylinders, each of which (in this particular C-H-S scheme) is a block of 1024 sectors, so when you give it cylinders, you're also giving it sectors. If you are aligned to 512K cylinders, you are most certainly aligned to the included 1024 sectors.

I don't know exactly what your planned installation will look like, but for the record, if you do need the separate partition for /boot, then you only need to make it a few hundred megabytes -- there's not a lot that goes in it. Since I recently made a /boot partition on an SSD that is 512K aligned, I will tell you exactly what you'll need:

start cylinder = 2
end cylinder = 1023

This will give you an approximately 500MB partition. Then your next (perfectly-aligned) partition can start at cylinder 1024. As you can see from my df output, the current contents of /boot (i.e. a couple of kernels and the grub files) on my system only amount to 43M:

root@aptosidbox:/home/don# df -h
Filesystem      Size Used Avail Use% Mounted on
/dev/sda1       51G 7.2G  41G 15% /
tmpfs         3.0G 8.0K 3.0G  1% /lib/init/rw
udev         3.0G 244K 3.0G  1% /dev
tmpfs         3.0G 1.2M 3.0G  1% /dev/shm
/dev/sdb1       56G  30G  23G 57% /mnt/REVODATA
/dev/sdc1       495M  43M 427M 10% /boot
/dev/sdc2       15G 165M  14G  2% /mnt/WHATEVER
/dev/sde       1.9T 407G 1.5T 22% /mnt/DATA
none         3.0G  40K 3.0G  1% /tmp
none         3.0G 8.3M 3.0G  1% /var/tmp
none         3.0G 492K 3.0G  1% /var/log
none         3.0G  20K 3.0G  1% /var/spool

The ext4 filesystem mount options are shown in my post on OCZ. Since my desktop system runs on a UPS, and I normally shut it down whenever I leave the house for more than a half-day, a loss of power to the computer is a very rare event. So I turn the journaling frequency down to once every 5 minutes -- I could probably double that and still sleep well. But that cuts it to 1/60 of the default 5-second frequency.

[oshunluvr]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Really you only need 100mb for a /boot partition. If you aligned on 128k rather than 512k you save some space. Of course, you don't need a /boot partition at all unless you're booting to a RAID0 or 5 install.

[dibl]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

If you aligned on 128k rather than 512k you save some space.

True ... however, note that OCZ Vertex 2 SSDs use 512K erase blocks. :P

[oshunluvr]

Re: newkomer to linux, new custom pc, need help/suggestions (long)

Ahhh! I see... 8)