ubuntu

Ubuntu 11 on Kingston SV100S2/256G SSD

abb — Sat, 08 Oct 2011 11:40:17 +0000

Ubuntu 11 on Kingston SV100S2/256G SSD

Here are some notes about my attempt to install Ubuntu 11 on Kingston SV100S2/256G SSD (on Dell Latitude E6510 laptop). Just in case somebody else finds it useful.

I have Googled around for information about SSD disk optimization for Linux and found that there are two main things to consider: partition alignment and filesystem options.

It appears to be important to (try to) align disk writes by the boundaries of SDD erase block size. This [1] article talks about LVM volumes alignment.

Most tutorials out there seems to blindly assume SSD erase block size is 128KB, unclear on what ground. This post [3] suggest the kind of disk I have features 1MB erase block size. I decided to take use this value.

Finally, I have ended up with the following partition layout, with alignment by 1MB:
$ sudo fdisk -S 64 -H 32 /dev/sdb ... Command (m for help): p

Disk /dev/sdb: 256.1 GB, 256060514304 bytes
32 heads, 63 sectors/track, 248074 cylinders
Units = cylinders of 2016 * 512 = 1032192 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xfeb3c9c1

Device Boot Start End Blocks Id System
/dev/sdb1 1 103 103792+ 83 Linux
/dev/sdb2 104 248074 249954768 8e Linux LVM

Creating LVM physical volume, with its meta-data size set to align start offset of its extents to with 1MB boundary.
$ sudo pvcreate --metadatasize 994k /dev/sdb2 Physical volume "/dev/sdb2" successfully created $ sudo pvs /dev/sdb2 -o+pe_start PV VG Fmt Attr PSize PFree 1st PE /dev/sdb2 lvm2 -- 238.38g 238.38g 1.00m

Create physical volume group and logical volume.
$ sudo vgcreate e6510-ssd1 /dev/sdb2 Volume group "e6510-ssd1" successfully created $ sudo lvcreate --size 32G --name root e6510-ssd1 Logical volume "root" created

Finally, create a file system, with stripe width set to 1MB (256 x 4K blocks). "Resize" parameter limits the maximum size your filesystem can grow live, it is optional parameter, just saves a few megabytes.
$ sudo mke2fs -t ext4 -E stripe-width=256,resize=250G /dev/e6510-ssd1/root

To make use the instructions above, you will need to use alternative installer CD which lets you interfere with partitioning/filesystem creation process.

References:
[1] http://thunk.org/tytso/blog/2009/02/20/aligning-filesystems-to-an-ssds-… (also available at http://web.archive.org/web/20101130200444/http://thunk.org/tytso/blog/2…)
[2] http://williamscott.me/blog/2010/12/ssd-tweaks-linux-align-partitions/
[3] http://forum.notebookreview.com/notebook-news-reviews/395398-kingston-s…

abb Sat, 10/08/2011 - 13:40

Self-encrypting (FDE) Hard Disks & Linux

abb — Thu, 03 Feb 2011 14:52:14 +0000

Self-encrypting (FDE) Hard Disks & Linux

Recently I have upgraded to Dell Latitude E6510 with 4 cores / 8 threads processor, plenty of RAM, and a fast hard disk. Nevertheless, the interactive performance of Ubuntu becomes sloppy beyond any measure when a virtual machine or two start trashing the disks.

There seems to be known performance problems in Linux kernel, like Bug 12309. And full disk encryption makes things even worse. It appears that new FDE technology will give laptop users a chance to move the burden of encryption to hard drives.

Some vendors already offer devices doing all the crypto stuff by themselves, on-the-fly, and supposedly with no performance impact whatsoever. I have heard about these drives a while ago, but just now came across this document from Seagate, which convinced me that their drive are likely to work in my laptop and Linux, or pretty much any laptop/OS with BIOS supporting password-protected hard drives.

I have just ordered ST9500421AS - Momentus 7200 FDE.2 500-GB Hard Drive for a bit over 62 euro before tax, we will see how it works out...

abb Thu, 02/03/2011 - 15:52

Build NetExpect on Ubuntu 10

abb — Tue, 26 Oct 2010 19:36:31 +0000

Build NetExpect on Ubuntu 10

I came across a nice tool, potentially useful for pen testing: TCP/IP-aware version of TCL expect. Written by Eloy Paris from Cisco Systems it is currently distributed in sources only. I didn't have much time to play with it yet, but it looks very promising. Tomorrow will try to use it for SIP REGISTER flooding, currently done with sipp. (In a way, SIPP is similar to NetExpect, can execute send-expect scenarios, but seems to be focused on SIP protocol.)

A bunch of slides illustrating what NetExpect can do can be found here.

On Ubuntu 10 installation goes as following (instructions at http://netexpect.org/wiki/PortabilityPage are for older versions of Ubuntu):

sudo apt-get install libglib2.0-dev tcl8.4-dev wireshark-dev libpcap-dev libdumbnet-dev libnet1-dev sudo mv /usr/include/pcap.h /usr/include/pcap.h- ./configure --prefix=/usr/local/netexpect-0.18 --with-tcl=/usr/lib/tcl8.4 --with-tcl-includes=/usr/include/tcl8.4 make sudo mv /usr/include/pcap.h- /usr/include/pcap.h sudo make install

The commands above will install the binaries under /usr/local/netexpect-0.18/bin.

abb Tue, 10/26/2010 - 21:36