Just moozing

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Installations gallore

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I have spend a lot of time installing stuff recently. In this blog entry, I have collected some of my thoughts and experiences.

Windows rantings

Windows 7 on a Lenovo E330. Go here for the long story – it was not pretty.

Windows 7 in a virtual machine. I had done that before, this time it was very difficult because of a broken hard disk. I mostly followed my own guide from last time.

It also made me realize that implementing a system using something like Clonezilla, requires you to have an image per PC, since that is what you accept in the license – so the thing about having 5-10 PCs with the same hardware is not doing much towards easing the administrative burden (if you follow the rules).

Also, Windows 7 64 bit version has system requirements of 2 GB RAM and 20 GB of disk space. That is a lot, if you want to run a couple of VMs in the same host – except you don’t want to do that because of the license. For server applications in a virtual environment, Linux’s possibility of removing all unnecessary stuff is very handy.

All that said, Window 7 (all variations) work nicely with KVM using virtio.

Server hardware

I have recently worked with HP Proliant micro servers. These are nice small servers with space for 4 hard disks. I set them up with Debian/Wheezy and 4 spinning disks in RAID 5.

Some benchmarking


# hdparm -tT /dev/sda

/dev/sda:
Timing cached reads:   3132 MB in  2.00 seconds = 1565.72 MB/sec
Timing buffered disk reads: 464 MB in  3.01 seconds = 154.14 MB/sec

# hdparm -tT /dev/md0

/dev/md0:
Timing cached reads:   3206 MB in  2.00 seconds = 1603.17 MB/sec
Timing buffered disk reads: 992 MB in  3.01 seconds = 329.94 MB/sec

Looking at these values, I conclude that it is not top-notch controller hardware (e.g. my Lenovo x230 has a cache read speed of approx. 10GB/s), but using RAID you get very good read speeds at low prices. This setup is good for a flexible NAS.

And adding 8 GB of memory, you can run non-intensive virtual machine servers also.

On large hard disks

In one of the Proliant servers, we installed 4x 3TB spinning disks. We learned that there is a new limit of 2 TB to consider.

On older installations, a /boot partition was needed due to addressing issues (LBA and CHS) and something about GRUB not understanding LVM, RAIDs and other fancy partitioning. GRUB2 can handle all that by now. Using disks larger than 2GB requires GPT partitions, and for GRUB to work a small partition is needed with the bios_grub flag.

We got it working, and the server (used as backup NAS) has 9 TB of disk space. It should be sufficient for now 🙂

On faulty SSDs disks

My Lenovo x230 laptop has an Intel 520 series 180 GB SDD disk. I have known that it had issues, but it was not untill recently that I found out what was wrong: it failed when I did lots of intensive write operations. It is not the kind of error I would expect from an “old” worn-out SSD.

This is not common, but I was able to recreate it when installing Pfsense or when running window 7 both virtual machines. The disk send bad info back to the controller and all file systems on the disk instantly remounted as read-only. It is bad to have filesystems containing root, /tmp, /home and /var remounted read-only, but the alternative is worse.

I tracked down other people having the same issue, and learned that there was no fix 😦

Talking to Lenovo, they told me to upgrade the firmware in the disk. They supply an ISO file to boot the system. This is a good solution, since the software must have exclusive rights to the SATA controller. It turned out that the ISO used some odd DOS version, and could not boot from USB.

Luckily, the good people on the Internet has solutions for these problems. I booted it, and it found that my firmware was the latest. After talking with Lenovo, they send me a new disk with the same specs, same make and same firmware.

I am currently testing it and it seems to work. I suspect that the disk will start to fail in 10-12 months – just like the first one.

 

Closing notes

  • I am working with metaconfig. It is a very handy configuration tool. More on that in a later post.
  • I am currently testing Fedora, since I want to do this. Also, Fedora is one of the big ones and I thought I ought to try using yum.
  • Pfsense is also very cool. I have been playing with NAT’ing and OSPF, and using Pfsense to link VLANs.
  • EUFI vs. old style BIOS is also something to be looked into. Current fix is to have the BIOS do “legacy” only…
  • How to make the system report if there is a problem with a RAID5 disk? and how to change it?
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Written by moozing

October 18, 2013 at 09:00

Posted in Tech

Tagged with , , ,

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