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RAID discs
by Chris Walker 31 May '13

31 May '13

Having seen that others are suffering RAID problems, perhaps now is an opportune time to ask about mine. I have an Edimax enclosure with 2 x 1TB discs in it. I got a notification from it yesterday to say that sdb had either failed or would fail within the next 24 hours. The drives were bought at the same time as the enclosure so given that one is failing or has failed, is it wise for me to replace both? The discs in there at the moment are Seagate drives and I don't think I specified anything special for them i.e. I just bought 2 discs. This time I'm going to go for something like a WD Red drive which are specified for NAS use. So 2 questions. Does anybody have any recommendations for discs or are the Western Digital discs ok? And second, should I replace both or is one ok for the time being?

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ftp problems
by Anthony Anson 31 May '13

31 May '13

Using up-to-date Mint, and happily using Fire FTP. Suddenly, half the page vanishes, leaving me with just the local side and a 'send' arrow. I can navigate through the local directories. Can't restore Fire FTP it to its proper configuration (AFAICS), so have been using Filezilla, mainly successfully - but - from time to time it connects, but the remote site spits my shaking-hand out. Status: Waiting to retry... Status: Connecting to ###.###.###.#:21... Status: Connection established, waiting for welcome message... Response: 438 Access denied. Please contact your support. Error: Could not connect to server (The :21... is kindly supplied by remote server, and should show there. It's a Linux server BTW.) Contacted Support and in the morning received two e-mails, just after I'd successfully ftpeed the file I tried to put up the evening before. No change in user, password or remote address data. Support has no idea why it wouldn't work the previous evening. *Could* the server be too busy, and <rhetoric> if so, couldn't it say so </rhetoric>? Any idea what 438 is? (I don't want to use a search injun using this dongle on GPRS unless I really have to...) -- Tony http://www.girolle.co.uk/

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Compaq Proliant servers going free
by mick 29 May '13

29 May '13

I'm not sure how many freeglers there are on this list, but I thought I'd pass this on anyway. "THREE complete Compaq PROLIANT 8500R servers offered in Eaton: http://norfolkfreegle.org/Post/ViewPost/13591" Mick --------------------------------------------------------------------- blog: baldric.net gpg fingerprint: FC23 3338 F664 5E66 876B 72C0 0A1F E60B 5BAD D312 ---------------------------------------------------------------------

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Software RAID error
by Mark Rogers 29 May '13

29 May '13

I'm having problems understanding what is happening on my RAID array. $ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sda1[0] sdb1[1](F) 976629568 blocks super 1.2 [2/1] [U_] To me, that suggests that sdb has failed, however, syslog contains lots of errors on sda but no mention of sdb. Amongst the things I've learned this morning, is the fact that I'm not getting any notifications; this only came to light because a VM that is hosted on this RAID array has lost the ability to write to one of its virtual disks (but not all of them). Should I conclude that both disks have failed? What is the best route to recovery here? Ie which disk do I swap out first with a new disk? Logically swapping out sda is the only thing that makes sense to me but advice welcomed. smartctl reports that neither disk had SMART enabled, which is odd because I thought they had, so there's no information there. I have enabled it this morning but don't want to try doing self-tests at this stage unless someone more knowledgeable than me says I should. Mark -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) @ 13 Clarke Rd, Milton Keynes, MK1 1LG

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Re: [ALUG] how to block new connections whilst allowing existing established
by mick 27 May '13

27 May '13

On Sun, 26 May 2013 20:34:24 +0100 Adam Bower <adam(a)thebowery.co.uk> allegedly wrote: > On Sun, May 26, 2013 at 08:09:07PM +0100, mick wrote: > > > > Before I start playing in earnest, does anyone know of a more > > elegant solution? > > Have you looked at profiling the connection length and how the client > works? I work for a CDN and to be honest since we acquired a > particular customer the scenario changed from us having a traffic > pattern that when taking a node out of our delivery group after 2 > hours it would see no connections, since this new customer even after > removing a node from delivery it will still see significant amounts > of traffic after 24 hours. > > The way we deal with it is to let some customers get "unlucky" but > then given the client immediately does a new dns lookup and goes to a > new server it means the interruption to them would be very brief. > > Anyhow, you might want to look at some kind of load balancer like > varnish for this scenario as if not a stuck connection might mean your > reboot never happens. > > Also, see if the clients can support range headers, if so they can > resume the download from the missing bit. This means it's not the end > of the world when a download fails. > Adam Thanks for this. But I should have said that my mirrors are on VMs in datacentres I don't control. So I have no chance of sticking a load balancing proxy in front of the servers. Furthermore, the "customers" are not paying me anything (I give the mirrors to the community) so I have no form of communication with them. I /could/ just be brutal, but I don't want to be - and as you will see from my answer to Nev, it turns out I don't have to be either. Cheers Mick --------------------------------------------------------------------- blog: baldric.net gpg fingerprint: FC23 3338 F664 5E66 876B 72C0 0A1F E60B 5BAD D312 ---------------------------------------------------------------------

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how to block new connections whilst allowing existing established
by mick 27 May '13

27 May '13

Hi guys I run a couple of mirrors serving "tails" over http. Occasionally I need to shut those servers down and reboot (for example I have just upgraded both of them to wheezy). Both servers are reasonably busy (they ship out about 2-3 TiB each per month) and normally have active connections at the time I want to power cycle them. Connections can (of course) come from anywhere and some people may be on slow lines and may be over half way through a download of one of the 700 meg iso files. If I simply power cycle the server they will likely lose the connection and the download. I'd like to be more friendly than that. So what I have in mind is some mechanism that I can invoke to prevent new connections being established but permit the existing ones to complete before I switch off. I've thought about cobbling together an iptables script which will change the lines: BLAH –dport 80 -m state –state NEW,ESTABLISHED -j ACCEPT to BLAH –dport 80 -m state –state ESTABLISHED -j ACCEPT temporarily and then switch it back afterwards. But I have yet to try it. Before I start playing in earnest, does anyone know of a more elegant solution? TIA Mick --------------------------------------------------------------------- blog: baldric.net gpg fingerprint: FC23 3338 F664 5E66 876B 72C0 0A1F E60B 5BAD D312 ---------------------------------------------------------------------

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Network printing again
by Chris Walker 25 May '13

25 May '13

I'm having another try at making network printing work. I bought a Buffalo ADSL router recently with the facility to print using the inbuilt USB port. I connected up the printer and tried to make my system see the it. But it never does. If I set the host address as 192.168.1.1, the system picks the port number as 9100. I've looked on the router and all I can see is a WebAccess External Port set to 9000 so I'm guessing that 9100 isn't likely to be about right. The router can also be used as a media server with a USB disc plugged in instead of the printer. If I do that, the disc is seen as smb://ap0024a5bdb4dc/disk1_pt1/ and I can see and read the files (the buffalo is seen on a wifi network as Buffalo-BDB4DC so that ties in too). But I'm still stuck as to why I can't print. Can anybody suggest a way forward please?

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Fire FTP trying to confuse me...
by Anthony Anson 23 May '13

23 May '13

and succeeding. Up to this morning Fire FTP has been intuitive and easy to use, however, from having a local and a remote side in separate panes on the same page, it has taken the liberty of listing everything on one side, and only having an upload arrow - no download one. I may have accidentally clicked something which has brought this about, but I can't find anything to restore the default position. Any ideas? -- Tony http://www.girolle.co.uk/

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DHCP Error
by steve-alug＠hst.me.uk 21 May '13

21 May '13

Hi folks, I'm confused about another thing too. I have an external backup drive, connected via a network cable. When things boot up, it gets IP addresses for its drives from my dhcp server. This used to work fine. Recently however, I find that the drive's complaining of a "DHCP network addressing problem" (according to the blinking light code!). If, before the drive boots I disable my UFW firewall with sudo ufw disable, then boot the drive, then enable the firewall, everything's OK. If I don't disable the firewall while the drive's getting an IP address, I get the error. I'm running dnsmasq as a dhcp server. My ufw rules are like this $ sudo ufw status Status: active To Action From -- ------ ---- 67 ALLOW 169.254.0.0/16 68 ALLOW 169.254.0.0/16 67 ALLOW 0.0.0.0 68 ALLOW 0.0.0.0 192.168.55.66 ALLOW 192.168.55.0/24 I've omitted 4 rules which open up specific ports, with a format like this as they're not relevant (at least I think they're not relevant) 192.168.55.66 123 ALLOW Anywhere 192.168.55.66 456/tcp ALLOW Anywhere As I understand it, the ports I need to allow access to are 67 and 68. When something asks for an IP address and it hasn't already got one, it broadcasts from the broadcast address 0.0.0.0. Sometimes, a machine will assign itself an IP address in the 169.254.0.0/16 range - e.g. a Windows machine that can't find a DHCP server on the network. If I allow this range then such machines can contact the DHCP server. The final line should allow anything with an address in the range 192.168.55.0 - 192.168.55.255 to contact any port on my server 192.168.55.66, which is where the DHCP server is. It seems to me I must have something wrong with the UFW rules, otherwise why would disabling it allow the drive to get a DCHP lease? What have I got wrong? Any ideas appreciated. Cheers Steve

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Network Engineering
by James Bensley 21 May '13

21 May '13

Hi All, I'm Not sure how many people know about the following here already, and hope fully this isn't against any list etiquette rules; I'm sure many of you use the various Stack Exchange sites, such as http://serverfault.com/, http://stackoverflow.com/, http://unix.stackexchange.com/ and http://askubuntu.com/. Now there is a new site that recently came out of Beta for public access, http://networkengineering.stackexchange.com/. If anyone has networking questions I urge you to sign up and start asking! If the site doesn't get enough traffic in this initial stages it could get shut down, and so far it is proving to be a great well of knowledge. Many thanks, James.

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