Recently in Performance Note Category

Mail (via imap clients) is no longer restricted.

In order to reduce the load on the storage server while to digests the replacement disk, I've turned of IMAP access to mail boxes.

You can read your mail via pine or http://mathmail.mcmaster.ca.

I'll be turning things on periodically to test the ability of the storage server to accept the mail load. Access from on-campus locations will be turned on before access from off campus.

The main server (ms) is still sluggish; consequently, the workstations and web sites are sluggish and mail delivery is slow. The storage array is still working to incorporate the replacement disk and so its performance is degraded - and that affects everything which stores data there.

There may be brief service interruptions (of up to five minutes) if I decide to shift load to another server.

The ms server and the workstations have been agonizingly slow (at best) since about 8:15 this morning. A disk on our main storage array failed and the array was hobbled (in "degraded mode", for those who follow these sorts of things). We do not yet know why performance was as miserable as it was - it should have been poor, not horrible.

There were three interruptions of five to ten minutes as I sought the cause of the problem - working on the invalid assumption that it was our server again.

The disk has been replaced and the storage array is rebuilding itself. Performance is going to be poor until the rebuild is complete.

Workstations may need to be rebooted if they have got confused over the state of the links to the home directories (though I have forced a refresh remotely on all systems which were responding).

The sluggishness was resolved at 3:30 this afternoon.

The server and most of the workstations (which access home directories on the server) are sluggish this afternoon due to an as-yet unidentified cause.

Some services (e.g. web, email) may go down for a few seconds at a time and workstations may freeze for up to half a minutes while I do some poking around.

We've had complaints of pine (and other command-line applications) being painfully slow in the past few weeks. It appears that this is almost always the result of logging in from off campus via VPN. Our own testing has shown that the slowness disappears when one shuts off VPN and connects directly to ms.mcmaster.ca.

We don't know yet whether this is a result of a change in the UTS VPN service or load or whether it might be due to an interaction between the new server and the UTS service ... though the former seems far more likely than the latter.

UTS is aware of the problem.

Our main server blew a disk this morning and is struggling while a spare is built into the main storage array. In order to allow the array to rebuild more quickly, I will be turning off mail services for up to half an hour at a time. Other services (workstations, Windows file sharing) may also be interrupted.

I will probably leave the interface at mail.math.mcmaster.ca up all the while, though.

Mathserv and dependent workstations and servers are a little slow right now due to some work I'm doing on the main file system. Things should be limber again by 9:45 pm.

The server and ms workstations are still sluggish at times as one server is still doing the bulk of the heavy service. This should be rectified by Tuesday.

The ms workstations became very slow for ten minutes at around 4 pm Friday - that was me running some updates which hammered the server harder than expected.

The server and workstations were a bit sluggish until ca. 9:45 am due to the nightly backups running later than usual (related to the power outage).

Mathserv and the msprime workstations were running sluggishly for about half an hour this afternoon due to an I/O problem on freesurface.

We are no longer backing up mail hourly during the day time: as often as not, the backups would slow down the server and msprime workstations noticably.

You may notice that mathserv and the linux workstations feel a bit laggy for approximately ten minutes at the top of each hour. This is because we have begun mirroring mail folders to the fail-over server every hour instead of once a day. We will be working on reducing the impact of these backups on system performance. Web and mail-client users shouldn't feel much of a difference; pine and graphical file browsing will be most strongly affected.