From: Petter Reinholdtsen <pere@hungry.com>
Date: Wed, 17 Jul 2013 21:56:54 +0000 (+0000)
Subject: New post.
X-Git-Url: https://pere.pagekite.me/gitweb/homepage.git/commitdiff_plain/dc802294a810e1f25f12428e5df9f2dd679f737f?hp=48db3b5787b109a981b3965e70a5480c43ea413a

New post.
---

diff --git a/blog/data/2013-07-17-new-laptop.txt b/blog/data/2013-07-17-new-laptop.txt
new file mode 100644
index 0000000000..7d67fef0fc
--- /dev/null
+++ b/blog/data/2013-07-17-new-laptop.txt
@@ -0,0 +1,90 @@
+Title: How to fix a Thinkpad X230 with a broken 180 GB SSD disk
+Tags: english, debian
+Date: 2013-07-17 23:50
+
+<p>Today I switched to
+<a href="http://people.skolelinux.org/pere/blog/The_Thinkpad_is_dead__long_live_the_Thinkpad_X230_.html">my
+new laptop</a>.  I've previously written about the problems I had with
+my new Thinkpad X230, which was delivered with an
+<a href="http://people.skolelinux.org/pere/blog/Intel_SSD_520_Series_180_GB_with_Lenovo_firmware_still_lock_up_from_sustained_writes.html">180
+GB Intel SSD disk with Lenovo firmware</a> that did not handle
+sustained writes.  My hardware supplier have been very forthcoming in
+trying to find a solution, and after first trying with another
+identical 180 GB disks they decided to send me a 256 GB Samsung SSD
+disk instead to fix it once and for all.  The Samsung disk survived
+the installation of Debian with encrypted disks (filling the disk with
+random data during installation killed the first two), and I thus
+decided to trust it with my data.  I have installed it as a Debian Edu
+Wheezy roaming workstation hooked up with my Debian Edu Squeeze main
+server at home using Kerberos and LDAP, and will use it as my work
+station from now on.</p>
+
+<p>As this is a solid state disk with no moving parts, I believe the
+Debian Wheezy default installation need to be tuned a bit to increase
+performance and increase life time of the disk.  The Linux kernel and
+user space applications do not yet adjust automatically to such
+environment.  To make it easier for my self, I created a draft Debian
+package <tt>ssd-setup</tt> to handle this tuning.  The
+<a href="http://anonscm.debian.org/gitweb/?p=collab-maint/ssd-setup.git">source
+for the ssd-setup package</a> is available from collab-maint, and it
+is set up to adjust the setup of the machine by just installing the
+package.  If there is any non-SSD disk in the machine, the package
+will refuse to install, as I did not try to write any logic to sort
+file systems in SSD and non-SSD file systems.</p>
+
+<p>I consider the package a draft, as I am a bit unsure how to best
+set up Debian Wheezy with an SSD.  It is adjusted to my use case,
+where I set up the machine with one large encrypted partition (in
+addition to /boot), put LVM on top of this and set up partitions on
+top of this again.  At the moment these parameters are tuned:
+
+<ul>
+
+<li>Set up cryptsetup to pass TRIM commands to the physical disk
+    (adding discard to /etc/crypttab)</li>
+
+<li>Set up LVM to pass on TRIM commands to the underlying device (in
+    this case a cryptsetup partition) by changing issue_discards from
+    0 to 1 in /etc/lvm/lvm.conf.</li>
+
+<li>Set relatime as a file system option for ext3 and ext4 file
+    systems.</li>
+
+<li>Tell swap to use TRIM commands by adding 'discard' to
+    /etc/fstab.</li>
+
+<li>Change I/O scheduler from cfq to deadline.</li>
+
+<li>Run fstrim on every ext3 and ext4 file system every night (from
+    cron.daily).</li>
+
+<li>Adjust sysctl values vm.swappiness to 1 and vm.vfs_cache_pressure
+    to 50 to reduce the kernel eagerness to swap out processes.</li>
+
+</ul>
+
+<p>I considered using the noop I/O scheduler, as several recommended
+it for SSD, but others recommended deadline and a benchmark I found
+indicated that deadline might be better for interactive use.</p>
+
+<p>I also considered using the 'discard' file system option for ext3
+and ext4, but read that it would give a performance hit ever time a
+file is removed, and thought it best to that that slowdown once a day
+instead of during my work.</p>
+
+<p>My package do not set up tmpfs on /var/run, /var/lock and /tmp, as
+this is already done by Debian Edu.</p>
+
+<p>I have not yet started on the user space tuning.  I expect
+iceweasel need some tuning, and perhaps other applications too, but
+have not yet had time to investigate those parts.</p>
+
+<p>The package should work on Ubuntu too, but I have not yet tested it
+there.</p>
+
+<p>As for the answer to the question in the title of this blog post,
+as far as I know, the only solution is to replace the disk.  It might
+be possible to flash it with Intel firmware instead of the Lenovo
+firmware.  But I have not tried and did not want to do so without
+approval from Lenovo as I wanted to keep the warranty on the disk
+until a solution was found and they wanted the broken disks back.</p>