blog/data/2013-07-17-new-laptop.txt

   1 Title: How to fix a Thinkpad X230 with a broken 180 GB SSD disk
   2 Tags: english, debian
   3 Date: 2013-07-17 23:50
   4
   5 <p>Today I switched to
   6 <a href="http://people.skolelinux.org/pere/blog/The_Thinkpad_is_dead__long_live_the_Thinkpad_X230_.html">my
   7 new laptop</a>.  I've previously written about the problems I had with
   8 my new Thinkpad X230, which was delivered with an
   9 <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
  10 GB Intel SSD disk with Lenovo firmware</a> that did not handle
  11 sustained writes.  My hardware supplier have been very forthcoming in
  12 trying to find a solution, and after first trying with another
  13 identical 180 GB disks they decided to send me a 256 GB Samsung SSD
  14 disk instead to fix it once and for all.  The Samsung disk survived
  15 the installation of Debian with encrypted disks (filling the disk with
  16 random data during installation killed the first two), and I thus
  17 decided to trust it with my data.  I have installed it as a Debian Edu
  18 Wheezy roaming workstation hooked up with my Debian Edu Squeeze main
  19 server at home using Kerberos and LDAP, and will use it as my work
  20 station from now on.</p>
  21
  22 <p>As this is a solid state disk with no moving parts, I believe the
  23 Debian Wheezy default installation need to be tuned a bit to increase
  24 performance and increase life time of the disk.  The Linux kernel and
  25 user space applications do not yet adjust automatically to such
  26 environment.  To make it easier for my self, I created a draft Debian
  27 package <tt>ssd-setup</tt> to handle this tuning.  The
  28 <a href="http://anonscm.debian.org/gitweb/?p=collab-maint/ssd-setup.git">source
  29 for the ssd-setup package</a> is available from collab-maint, and it
  30 is set up to adjust the setup of the machine by just installing the
  31 package.  If there is any non-SSD disk in the machine, the package
  32 will refuse to install, as I did not try to write any logic to sort
  33 file systems in SSD and non-SSD file systems.</p>
  34
  35 <p>I consider the package a draft, as I am a bit unsure how to best
  36 set up Debian Wheezy with an SSD.  It is adjusted to my use case,
  37 where I set up the machine with one large encrypted partition (in
  38 addition to /boot), put LVM on top of this and set up partitions on
  39 top of this again.  See the README file in the package source for the
  40 references I used to pick the settings.  At the moment these
  41 parameters are tuned:</p>
  42
  43 <ul>
  44
  45 <li>Set up cryptsetup to pass TRIM commands to the physical disk
  46     (adding discard to /etc/crypttab)</li>
  47
  48 <li>Set up LVM to pass on TRIM commands to the underlying device (in
  49     this case a cryptsetup partition) by changing issue_discards from
  50     0 to 1 in /etc/lvm/lvm.conf.</li>
  51
  52 <li>Set relatime as a file system option for ext3 and ext4 file
  53     systems.</li>
  54
  55 <li>Tell swap to use TRIM commands by adding 'discard' to
  56     /etc/fstab.</li>
  57
  58 <li>Change I/O scheduler from cfq to deadline using a udev rule.</li>
  59
  60 <li>Run fstrim on every ext3 and ext4 file system every night (from
  61     cron.daily).</li>
  62
  63 <li>Adjust sysctl values vm.swappiness to 1 and vm.vfs_cache_pressure
  64     to 50 to reduce the kernel eagerness to swap out processes.</li>
  65
  66 </ul>
  67
  68 <p>During installation, I cancelled the part where the installer fill
  69 the disk with random data, as this would kill the SSD performance for
  70 little gain.  My goal with the encrypted file system is to ensure
  71 those stealing my laptop end up with a brick and not a working
  72 computer.  I have no hope in keeping the really resourceful people
  73 from getting the data on the disk (see
  74 <a href="http://xkcd.com/538/">XKCD #538</a> for an explanation why).
  75 Thus I concluded that adding the discard option to crypttab is the
  76 right thing to do.</p>
  77
  78 <p>I considered using the noop I/O scheduler, as several recommended
  79 it for SSD, but others recommended deadline and a benchmark I found
  80 indicated that deadline might be better for interactive use.</p>
  81
  82 <p>I also considered using the 'discard' file system option for ext3
  83 and ext4, but read that it would give a performance hit ever time a
  84 file is removed, and thought it best to that that slowdown once a day
  85 instead of during my work.</p>
  86
  87 <p>My package do not set up tmpfs on /var/run, /var/lock and /tmp, as
  88 this is already done by Debian Edu.</p>
  89
  90 <p>I have not yet started on the user space tuning.  I expect
  91 iceweasel need some tuning, and perhaps other applications too, but
  92 have not yet had time to investigate those parts.</p>
  93
  94 <p>The package should work on Ubuntu too, but I have not yet tested it
  95 there.</p>
  96
  97 <p>As for the answer to the question in the title of this blog post,
  98 as far as I know, the only solution I know about is to replace the
  99 disk.  It might be possible to flash it with Intel firmware instead of
 100 the Lenovo firmware.  But I have not tried and did not want to do so
 101 without approval from Lenovo as I wanted to keep the warranty on the
 102 disk until a solution was found and they wanted the broken disks
 103 back.</p>