ISG News has posted a new item, 'HIT Building: Electric Power Interruption on
Wednesday, 25th of July'
Due to maintenance work relating the electric power supply of the HIT building
there will be a planed interruption from 5:00am to 8:00am on Wednesday the 25th
of July.
Please note that the whole HIT building will be without electric power during
this time (The server room HIT D 13 is excepted from this interruption).
Shutdown your computer and switch off (use main switch if available or unplug)
your electrical devices in advance to avoid local data loss and help prevent
start-up peaks when electric power is switched back on.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/07/16/hit-building-electric-power-interr…
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posted.
Best regards,
thomber
thomber(a)phys.ethz.ch
ISG News has posted a new item, 'Login Server Downtime'
Apart from the file-, mail- and web servers exists another crucial element of
our core server infrastructure, namely the servers managing the account
information and logins (LDAP). With a current uptime of a remarkable 550 days,
it is time for an upgrade of the operating system and high-availability cluster
software. For this reason we schedule a downtime on Wednesday 18th July between
07:00 and 08:00.
Most services will be affected and unavailable during that time, as they require
an authentication with your D-Phys account (email, file server, print server,
managed workstations). Note that, even though you will not be able to check your
emails or send new ones, all incoming mails will be received and safely
delivered to your inbox afterwards.
If everything goes smoothly, the actual downtime should be considerably less
than the scheduled hour.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/07/13/login-server-downtime/
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Claude Becker
becker(a)phys.ethz.ch
ISG News has posted a new item, 'Short Mail Server Downtime on Friday Late
Afternoon'
We have scheduled a downtime of the D-PHYS mail server for hardware maintenance
on Friday, 1st of June 2012, starting after 4pm and lasting approximately half
an hour. During the downtime sending and receiving mails will not be possible.
Incoming mails will be slightly delayed.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/05/31/short-mail-server-downtime/
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Axel Beckert
beckert(a)phys.ethz.ch
ISG News has posted a new item, 'Mobile printing'
Until now it was not possible to print on D-PHYS printers while you're on the
road with mobile devices. Since several people expressed their interest in such
a possibility, we have created two methods that allow you to do just that: read
more.
As there's no common standard for mobile printing, certain restrictions apply.
If you find yourself with an email that you think should print but doesn't,
please let us know.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/05/07/mobile-printing/
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Christian Herzog
daduke(a)phys.ethz.ch
ISG News has posted a new item, 'The Art of Scaling'
Note: this is a purely anecdotal posting about our struggles with some
performance bottlenecks in the last few months. If you're not interested in such
background information, just skip.
You might have noticed that since about January 2012 using our file and mail
servers hasn't been as smooth as usual. This posting will give you some
background information concerning the challenges we encountered and why it took
so long to fix them. Let's begin with the file server.
Way back in the days (i.e. 5 years ago), when the total file server data volume
at D-PHYS was about 10 TB, we used individual file server to store this data.
When one server was full, we got a bigger one, copied all the data and life was
good for another year or two. Today, the file server data volume (home and group
shares) is above 150 TB and growing fast and this strategy doesn't work any
longer: individual servers don't scale and copying this amount of data alone
takes weeks. That's why in 2009 we started migrating the 'many individual
servers' setup to a SAN architecture in which the file servers are just huge
hard drives (iSCSI over Infiniband, for the technically inclined) connected to a
frontend server that manages space allocation and the file system. The same is
true for the backup infrastructure, where the data volume is even bigger.
This new setup had to be developed, tested and put in place as seamlessly and
unobtrusively as possible while ensuring data access at all times (apart from
single hour-long migrations). The SAN architecture was implemented for Astro in
December 2010 and has been running beautifully ever since. In 2011 we laid the
groundwork to adopt this system for the rest of D-PHYS's home and group shares
and after a long and thorough testing period the rollout happened on January 5,
2012. Unfortunately, that's when things got ugly.
At first, we noticed some exotic file access problems on 32bit workstations. It
took us some time to understand that the underlying issue was an incompatibility
with the new filesystem using 64-bit addresses for the data blocks. As a
consequence we had to replace the filesystem of the home shares. Independently
we ran into serious I/O issues with the installed operating system, so we had to
upgrade the kernel of the frontend server and move the home directories onto a
dedicated server. In parallel, we had to incorporate some huge chunks of group
data while always making sure that nightly backups were available. All this
necessitated a few more migrations until we finally achieved a stable system on
March 28.
The upshot: what we had hoped to be a fast and easy migration turned out to
cause a lot of problems and take much longer than anticipated, but now we have a
stable and solid setup that will scale up to hundreds or even thousands of TB of
data.
See live volume management and usage graphs for our file servers.
As for the mail server, matters are to some extent related and partly just
coincidental in time. The IMAP server does need access to the home directories
and hence also suffered when their performance was impaired. But even after
having solved the file server issues, we still saw single load peaks on the IMAP
server that prevented our users from working with their email. Again, we put a
lot of time and effort into finding the reason. As of April 13, we're back to
good performance and arrive at the following set of conclusions:
Particular issues:
a covertly faulty harddisk in the mail server RAID seems to have impaired
performance
CPU load of the individual virtual machines on the mail server was not
distributed across the available CPU cores in an optimal way
General mail server load:
while incoming mail volume doesn't increase much, outgoing mails have grown 50%
in the last year alone
more and more sophisticated spam requires more thorough virus and spam scanning,
increasing the load on the mail server
our users have amassed 1.1 TB of mail storage (up from 400 GB in January 2010),
which need to be accessed and organized
Bottom line:
We'd like to thank you for your patience during the last 4 months and apologize
for any inconvenience you might have had to endure. In all likelihood the
systems will be a lot more stable in the future, but of course we're constantly
working to ensure the D-PHYS IT infrastructure is able to keep up with the fast
growing demand of disk space (the data volume has tripled in the last year
alone). We've learned a lot and we'll put it to good use.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/04/19/the-art-of-scaling/
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Christian Herzog
daduke(a)phys.ethz.ch
ISG News has posted a new item, 'Mail Server Maintenance Downtime this Evening'
For some hardware and other maintenance we schedule a downtime of our mail
server today (Fri, 13th of April 2012) evening after 6pm.
The downtime will likely take less than one hour. During the downtime you will
neither be able to access your mails on the server nor to send mails via our
server. Mails which are sent to the Dept. of Physics won't get lost, but will
have some lag.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/04/13/mail-server-maintenance-downtime/
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Axel Beckert
beckert(a)phys.ethz.ch
ISG News has posted a new item, 'Temporary SMB access restriction'
Last night a security problem was detected in the SMB server software we use for
our group and home shares. In order to protect your data and our systems, we
temporarily restrict access to our group and home shares to the ETHZ IP address
range
until security updates are available. If you're outside the ETH network and need
to access your data, use VPN. We expect the updates to be released later today
or tomorrow and will then go back to world wide access.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/04/11/temporary-smb-access-restriction/
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Christian Herzog
daduke(a)phys.ethz.ch
ISG News has posted a new item, 'Migration of Home Directories'
In order to restructure the filesystem of the home directories, we schedule a
migration on
Wednesday, 28. March 2012, starting at 17:00 and lasting for several hours.
During this time the home directories (winhome, machome, unixhome), the mail
services and some websites will not be available.
To protect you from losing or corrupting any of your files, we strongly
recommend you close all open files on the home directories before the
migration.
Since we have switched to generic names for our services, the home directories
will still be accessible the same way as before after the migration is over, so
you don't have to change anything.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/03/16/migration-of-home-directories/
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Schmid Patrick
schmid(a)phys.ethz.ch
ISG News has posted a new item, 'HIT Building: Network Interruption next Friday
Morning, 9th of Mars'
ID-Kom plans to upgrade the access routers of the HIT building next Friday
morning (9th of Mars) between 6:00 and 7:30am. This causes a network
interruption for about 15 minutes during this time in the HIT building.
All D-PHYS Servers located in HIT D 13 are not affected by this interrupt and
are reachable from outside the HIT building at any time.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/03/06/hit-building-network-interruption-…
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
thomber
thomber(a)phys.ethz.ch
ISG News has posted a new item, 'Short maintenance downtime on Sun, Feb 12'
Yesterday's outage could be traced to a flaky voltage controller on one of our
RAID adapters. We schedule a short maintenance downtime on
Sunday, Feb 12, around 13:00
in order to replace the faulty controller. Most services will be affected.
You may view the latest post at
https://nic.phys.ethz.ch/news/2012/02/10/short-maintenance-downtime-on-sun-…
You received this e-mail because you asked to be notified when new updates are
posted.
Best regards,
Christian Herzog
daduke(a)phys.ethz.ch