swap partition leads to instability?
hi everyone, I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. so my question is simple: - could having a swap partition, be a bad thing for my FreeBSD server? and if so, why and in what conditions? Cheers! ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
Hi, On Sun, 26 May 2013 01:58:32 -0700 (PDT) M. V. bored_to_deat...@yahoo.com wrote: I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. because it is a false claim. I never ever have had any system with working hard, that gave a problem because of the swap space. Erich ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
On Sun, 26 May 2013 16:09:06 +0700, Erich Dollansky wrote: Hi, On Sun, 26 May 2013 01:58:32 -0700 (PDT) M. V. bored_to_deat...@yahoo.com wrote: I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. because it is a false claim. I never ever have had any system with working hard, that gave a problem because of the swap space. I think the problem here is that he's using a SSD. As soon as the swap partition is being in heavy use, which means it receives many writes, this may lead to the SSD wearing out, decreasing its lifetime. Swap space usually does not make a system unstable. Sometimes, the opposite is true. :-) So if you're using a SSD, you can apply certain optimizations to increase its lifetime so it can be in use for several years (running 24/7). Here are some suggestions -- check if they are useful in your specific case! # newfs -m 0 -i 16384 -b 16384 -f 2048 -U /dev/ada0a This assumes that you don't have created any slices, just one bootable partition covering the whole disk (therefor ada0a). Create a swapfile like this: # /bin/rm -f /swapfile.tmp # /bin/dd if=/dev/zero of=/swapfile.tmp bs=16m seek=1k count=0 # /sbin/mdconfig -a -t vnode -u 0 -f /swapfile.tmp || /bin/sh # /bin/chflags nodump /swapfile.tmp # /bin/rm -f /swapfile.tmp # /sbin/swapctl -a /dev/md0 This makes the system use a disk-backed dynamic swap file. If the swap won't be used, no space will be occupied or reserved on the SSD. You can also think about changing stuff you won't need to store on the SSD, maybe some content of /tmp or /var. You can also put those into a memory disk. The SSD rule is: Minimize writes if you can. This is a _general_ rule and does not correspond to swap only! -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
On Sun, 26 May 2013 01:58:32 -0700 (PDT) M. V. bored_to_deat...@yahoo.com wrote: hi everyone, I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. so my question is simple: - could having a swap partition, be a bad thing for my FreeBSD server? and if so, why and in what conditions? I never had a problem with swap partitions, but perhaps the FreeBSD expert may refer to one of this three issues I can think about problems with swap, none of them are unstability issues: a) Swap partitions may store info from previous boot, you can use swap encryption for that. b) When using swap files (mounting a swap in a file), at shutdown sometimes there's a race condition and swap is unmounted before it's empty. c) If your system needs to use swap, network apps may show/throw timeouts when swap i/o is heavy. Sometimes b) kicks me but it's my fault because i don't shutdown process properly. Cheers! L --- --- Eduardo Morras emorr...@yahoo.es ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
Hi, sorry for my English. Here is what I wanted to say. On Sun, 26 May 2013 16:09:06 +0700 Erich Dollansky erichsfreebsdl...@alogt.com wrote: Hi, On Sun, 26 May 2013 01:58:32 -0700 (PDT) M. V. bored_to_deat...@yahoo.com wrote: I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. because it is a false claim. I never ever have had any system with working hard, that gave a problem because of the swap space. I never ever have had any system which was working hard that gave problems because of the swaps space. Erich Erich ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
On 26/05/2013 09:58, M. V. wrote: hi everyone, I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. so my question is simple: - could having a swap partition, be a bad thing for my FreeBSD server? and if so, why and in what conditions? Having a swap partition is absolutely standard for server or workstation class machines, and should be implemented as a matter of course. Even if the machine has much more memory than it would generally ever use and so have no actual need to swap. About the only circumstances where you wouldn't want swap is if you were creating an embedded appliance and eg. didn't have any writable disk space. That's pretty extraordinary and as such a system would have to be heavily customized over stock FreeBSD anyhow, so not having swap would fade into insignificance compared to the other changes that would be required. Why is swap needed? Nowadays, memory is sufficiently cheap and system boards are capable of loading so much of it, that the only sensible strategy is to have more physical RAM than is required to keep your normal application load working. So a swap partition should not be routinely involved in swapping memory pages back and forth. Even so, idle pages can be swapped out -- there's no point in having an unreferenced memory page sitting in RAM taking up space that could be used productively by an active process. A small amount of swap usage like this is standard. A large amount of swap usage like this indicates you need to switch to using better written software. Swap is also useful to buffer against unexpected spikes in memory usage. Sure, performance generally nosedives once a system starts actively swapping, but that may be a better outcome than the alternative if there is no swap capacity available: which is for the kernel to start killing off processes in an attempt to reduce memory pressure. Finally, swap is used as the place to record kernel state in the event of system crashes. You could use any otherwise unused disk partition for that, but swap is traditional. This is where the hoary old recipe of 'swap = twice ram' came from, although nowadays what with minidumps and the generally larger amounts of RAM in use you don't need to provide anything like as much as that. If you're bothered by having a few GiB of disk allocated as swap but basically idle, then look into tmpfs or mdmfs for /tmp -- that will let you make productive use the space while still keeping the ability to save crashdumps if needed. Some caveats about where to put a swap area: * If your system is under memory pressure, then your swap area can be extremely active. In these circumstances putting swap on a SSD card or other device with a limited number of write-cycles is not a good choice. * If you are using ZFS, and again, if you are under memory pressure, then putting swap on a ZFS can lead to a deadlock where the system needs to allocate more memory to deal with an out-of-memory condition. In this case, it is recommended to create a separate swap partition not managed by ZFS. Otherwise, swap can go anywhere. A dedicated partition will give better performance than swapping to a file, but file-backed swap is handy if you need to add swap in a hurry. For resilience, mirror swap partitions in pairs -- gmirror(8) is a good tool for that. Don't try using any of the higher RAID levels for swap areas -- their performance characteristics are not a good match to the sort of IO a swap area does. For best performance, you should spread swap areas over as many disk spindles as possible. You can create numerous swap areas and the system will automatically stripe any IO across them. Cheers, Matthew -- Dr Matthew J Seaman MA, D.Phil. PGP: http://www.infracaninophile.co.uk/pgpkey signature.asc Description: OpenPGP digital signature
How to switch Datgram/Connected mtu modes?
Hello. I work with FreeBSD 9.1 and Mellanox devices. How can I configure MTU in connected mode on FreeBSD 9.1? In Linux to enable connected mode for interface ib0, I enter: echo connected /sys/class/net/ib0/mode Switching between CM and UD mode can be done in run time: echo datagram /sys/class/net/ib0/mode sets the mode of ib0 to UD echo connected /sys/class/net/ib0/mode sets the mode ib0 to CM There is no such directories at FreeBSD. Wat shall I do? Datagram vs Connected modes The IPoIB driver supports two modes of operation: datagram and connected. The mode is set and read through an interface's /sys/class/net/intf name/mode file. In datagram mode, the IB UD (Unreliable Datagram) transport is used and so the interface MTU has is equal to the IB L2 MTU minus the IPoIB encapsulation header (4 bytes). For example, in a typical IB fabric with a 2K MTU, the IPoIB MTU will be 2048 - 4 = 2044 bytes. In connected mode, the IB RC (Reliable Connected) transport is used. Connected mode takes advantage of the connected nature of the IB transport and allows an MTU up to the maximal IP packet size of 64K, which reduces the number of IP packets needed for handling large UDP datagrams, TCP segments, etc and increases the performance for large messages. In connected mode, the interface's UD QP is still used for multicast and communication with peers that don't support connected mode. In this case, RX emulation of ICMP PMTU packets is used to cause the networking stack to use the smaller UD MTU for these neighbours. Thanks a lot Regards, Alex Liptsin Office: +972 (74) 7236141 Mobile: +972(54) 7833986 Fax: +972(74) 7236161 Email: al...@mellanox.commailto:al...@mellanox.com ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
a copy of ASL dump for acer aspire laptops models
Hi everyone, I need a copy of ACPI Source Language (ASL), '# acpidump-dt copy_model_laptop.asl' of any version of FreeBSD you have the option ACPI always enabled and does not give any problem on ACER laptops. Anyone can send me a copy of your ASL dump ( see above ) of ACER ASPIRE laptops model? Thanks, see you. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
M. V. bored_to_death85 at yahoo.com writes: hi everyone, I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. so my question is simple: - could having a swap partition, be a bad thing for my FreeBSD server? and if so, why and in what conditions? Cheers! Hi, I think your FB expert was up to something. I bet he spoke out of experience. Swapping by itself can decrease system reliability due to possible data corruption on swap disk or during two-way transfers, with subsequent incorrect RAM and machine crash. But, swapping is also a symptom, not a problem. It is never a good idea to let it get to that point. Badly written, architected, or tuned server app or system are the reason. Think of RDBMS/SQL server processing real-time on-line transactions and how much it goes into setting it up properly for a heavy use. On a smaller scale, consider this example: http://blog.jcole.us/2010/09/28/mysql-swap-insanity-and-the-numa-architecture/ jb ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: a copy of ASL dump for acer aspire laptops models
Hi, Reference: From: Xavier xavierfreebsdquesti...@gmail.com Date: Sun, 26 May 2013 14:21:04 +0200 Xavier wrote: Hi everyone, I need a copy of ACPI Source Language (ASL), '# acpidump-dt copy_model_laptop.asl' of any version of FreeBSD you have the option ACPI always enabled and does not give any problem on ACER laptops. Anyone can send me a copy of your ASL dump ( see above ) of ACER ASPIRE laptops model? Hi, I have an acer/aspire/5741 no problems I'm aware of, so will send you mine. uname -a FreeBSD lapr.js.berklix.net 9.1-RELEASE FreeBSD 9.1-RELEASE #3: Tue Apr 9 14:33:17 CEST 2013 j...@lapr.js.berklix.net:/sys/amd64/compile/LAPR.small amd64 I'm not sure what you mean at you have the option ACPI always enabled and does not give any problem however, sysctl -a | grep -i acpi does show device acpi 136 lines in total, acpidump -dt produces 15,840 lines, so I'll not append to list but private mail you. Anything else you need ? What's wrong ? What you are you chasing ? PS mob...@freebsd.org or a...@freesbd.org would be better best lists for this, not questions@. http://lists.freebsd.org/mailman/listinfo/freebsd-acpi http://lists.freebsd.org/mailman/listinfo/freebsd-mobile so I added cc: freebsd-a...@freebsd.org Cheers, Julian -- Julian Stacey, BSD Unix Linux C Sys Eng Consultant, Munich http://berklix.com Reply below not above, like a play script. Indent old text with . Send plain text. No quoted-printable, HTML, base64, multipart/alternative. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: a copy of ASL dump for acer aspire laptops models
Hi Xavier cc questions@ acpi@ I wrote: acpidump -dt produces 15,840 lines, so I'll not append to list but private mail you. I put it here so others on acpi@ questions@ can look too if they want. http://berklix.com/~jhs/hardware/laptops/acer/aspire/5741/ Cheers, Julian -- Julian Stacey, BSD Unix Linux C Sys Eng Consultant, Munich http://berklix.com Reply below not above, like a play script. Indent old text with . Send plain text. No quoted-printable, HTML, base64, multipart/alternative. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
RE:
Gustav%20Linde399 http://spsp2.free.fr/w/52Clare%20Lanman230 Mon, 27 May 2013 20:27:12 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Gateway on downloads
Hi all, netstart -rn (partitially) DestinationGatewayFlagsRefs Use Netif Expire default10.10.10.100 UGS 0 858468 re0 Can you tell me how I can force _any_download from my server not going via 10.10.10.100 but to another gateway number 10.10.10.200? For incoming uploads (ftp) and domain requests (Apache) still to keep 10.10.10.100 for incoming traffic. I have NZBGet installed and want to use the 2nd gateway (triple time the 1st gateway speed) on downloads. Maybe there is a way on ftp/download requests to redirect certain destination IP's to be switch through another network gateway IP? Thanks, Jos Chrispijn ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
The Intel SLC mSATA drives I use in embedded devices don't support TRIM, but - it doesn't seem to matter. Actually, I'm confident that just using bare partitions for swap is fine, and I haven't had any of the trouble I witnessed with MLC devices. The difference is that the size is limited to under 32GB. - M On Sun, May 26, 2013 at 4:32 PM, Warren Block wbl...@wonkity.com wrote: On Sun, 26 May 2013, Polytropon wrote: On Sun, 26 May 2013 16:09:06 +0700, Erich Dollansky wrote: Hi, On Sun, 26 May 2013 01:58:32 -0700 (PDT) M. V. bored_to_deat...@yahoo.com wrote: I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. because it is a false claim. I never ever have had any system with working hard, that gave a problem because of the swap space. I think the problem here is that he's using a SSD. As soon as the swap partition is being in heavy use, which means it receives many writes, this may lead to the SSD wearing out, decreasing its lifetime. Another problem with SSDs is that they can have difficulty with wear leveling. This is even worse with swap because there is no way to use TRIM to tell the SSD about blocks that have been freed. The workaround is a swapfile on UFS with TRIM enabled. It works fine, and even better when you update the rc scripts for shutdown. Here's an article on setup: http://www.wonkity.com/~**wblock/docs/html/ssd.htmlhttp://www.wonkity.com/~wblock/docs/html/ssd.html And here is the PR with a patch: http://www.freebsd.org/cgi/**query-pr.cgi?pr=bin/168544http://www.freebsd.org/cgi/query-pr.cgi?pr=bin/168544 __**_ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/**mailman/listinfo/freebsd-**questionshttp://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-** unsubscr...@freebsd.org freebsd-questions-unsubscr...@freebsd.org ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
On Sun, 26 May 2013, Polytropon wrote: On Sun, 26 May 2013 16:09:06 +0700, Erich Dollansky wrote: Hi, On Sun, 26 May 2013 01:58:32 -0700 (PDT) M. V. bored_to_deat...@yahoo.com wrote: I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a long time now. But recently I heard from a FreeBSD expert that I shouldn't have swap partition for my server, and having swap partition could make my server unstable. this was so strange for me, and I searched a lot but couldn't find a reason for this claim. because it is a false claim. I never ever have had any system with working hard, that gave a problem because of the swap space. I think the problem here is that he's using a SSD. As soon as the swap partition is being in heavy use, which means it receives many writes, this may lead to the SSD wearing out, decreasing its lifetime. Another problem with SSDs is that they can have difficulty with wear leveling. This is even worse with swap because there is no way to use TRIM to tell the SSD about blocks that have been freed. The workaround is a swapfile on UFS with TRIM enabled. It works fine, and even better when you update the rc scripts for shutdown. Here's an article on setup: http://www.wonkity.com/~wblock/docs/html/ssd.html And here is the PR with a patch: http://www.freebsd.org/cgi/query-pr.cgi?pr=bin/168544 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
On Sun, May 26, 2013 at 6:32 PM, Warren Block wbl...@wonkity.com wrote: Another problem with SSDs is that they can have difficulty with wear leveling. This is even worse with swap because there is no way to use TRIM to tell the SSD about blocks that have been freed. Um, that is wrong. It is in fact the basically the point of TRIM. And SSD's typically use the best form of wear leveling and it's usually advisable to leave a bit of the drive unpartitioned/unused to ensure the wear leveling works optimally. -- Adam Vande More ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
On Sun, 26 May 2013, Adam Vande More wrote: On Sun, May 26, 2013 at 6:32 PM, Warren Block wbl...@wonkity.com wrote: Another problem with SSDs is that they can have difficulty with wear leveling. This is even worse with swap because there is no way to use TRIM to tell the SSD about blocks that have been freed. Um, that is wrong. Which part? A FreeBSD swap partition has no way to use TRIM, so I suggest using a swap file on top of UFS, which does support TRIM. It is in fact the basically the point of TRIM. And SSD's typically use the best form of wear leveling and it's usually advisable to leave a bit of the drive unpartitioned/unused to ensure the wear leveling works optimally. Using TRIM should preserve performance better than leaving unused space and letting the drive wear leveling algorithm move data around without the hint. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Case sensitive usernames and sendmail - mystic voodoo
List, Step1: Make a new user:: root@localhost# pw useradd foo -m -s /bin/tcsh -h 0 password for user foo: (secret) Step 2: Does sendmail know them:: root@modunix# sendmail -bv foo@localhost foo@localhost... deliverable: mailer local, user foo # Good... Step 3: Make a new user with uppercase 'B':: root@localhost# pw useradd Bar -m -s /bin/tcsh -h 0 password for user Bar: (secret) Step 4: Does sendmail know them:: root@modunix# sendmail -bv Bar@localhost Bar@localhost... User unknown Curious, why? I know usernames are case-sensitive, I thought emails were too. Without fighting an epic battle with with the sendmail configs, is there a simple way to make this work? The obvious answer is probably, usernames should be lowercase! and for new users I'll enforce that policy. For existing users however, who may already have lots of case-sensitive usernames in various config files, etc this isn't a real option. By just altering their usernames I'm afraid I'd break the whole damn universe. How can I enable mail for them? Cheers! -Modulok- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Case sensitive usernames and sendmail - mystic voodoo
Hi, On Sun, 26 May 2013 18:44:41 -0600 Modulok modu...@gmail.com wrote: List, Step1: Make a new user:: root@localhost# pw useradd foo -m -s /bin/tcsh -h 0 password for user foo: (secret) Step 2: Does sendmail know them:: root@modunix# sendmail -bv foo@localhost foo@localhost... deliverable: mailer local, user foo # Good... Step 3: Make a new user with uppercase 'B':: root@localhost# pw useradd Bar -m -s /bin/tcsh -h 0 password for user Bar: (secret) Step 4: Does sendmail know them:: root@modunix# sendmail -bv Bar@localhost Bar@localhost... User unknown Curious, why? I know usernames are case-sensitive, I thought emails were too. Without fighting an epic battle with with the sendmail configs, is there a simple way to make this work? The obvious answer is probably, usernames should be lowercase! and for new users I'll enforce that policy. For existing users however, who may already have lots of case-sensitive usernames in various config files, etc this isn't a real option. By just altering their usernames I'm afraid I'd break the whole damn universe. How can I enable mail for them? have you read this? http://www.linuxquestions.org/questions/linux-software-2/sendmail-unable-to-find-users-22290/ Erich ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: swap partition leads to instability?
On Sun, May 26, 2013 at 7:20 PM, Warren Block wbl...@wonkity.com wrote: Which part? This part: Another problem with SSDs is that they can have difficulty with wear leveling. Do as I suggested and you'll get maximum life from the drive even with swap present. Even absent of best practices, SSD's in general do a great job in managing wear leveling. We're 5+ years out from crappy SSD's with dynamic wear leveling. Modern SSD's don't suffer nearly the write amplification effect of earlier drives. Also the write amplification effect only comes into play during random writes. A lot of common swap usage isn't random. All this is of course assuming we're dealing with a quality drive. If you're using a cheap Chinese knock off, all bets are off. A FreeBSD swap partition has no way to use TRIM, so I suggest using a swap file on top of UFS, which does support TRIM. Using TRIM should preserve performance better than leaving unused space and letting the drive wear leveling algorithm move data around without the hint. Normal dynamic wear leveling on a modern SSD will be better than imposing an FS- backed swap for 4GB partion occupying a small fraction of total drive space. File backed paging imposes two sets of bottlenecks and TRIM only *helps* with one. Another part of the equation is how much is swap used. If rarely, this is a non-issue to begin with. If it's significant, any flash SSD probably isn't appropriate. Certain other SSD's are not subject to these guidelines at all. -- Adam Vande More ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Case sensitive usernames and sendmail - mystic voodoo
On Sun, 26 May 2013 18:44:41 -0600, Modulok wrote: I know usernames are case-sensitive, I thought emails were too. If I remember e-mail basics correctly: No. They're not. For example, f...@example.com, f...@example.com and f...@example.com and all upper/lowercase variations are the same as f...@example.com. For sending mail within a system and across systems, names in the passwd file have to be in conjunction with the respective mail queues for the users. Even foo and Foo can coexist (as soon as they have a different UID, reflecting the fact that two distinguishable users are intended), but regarding mail... that sounds problematic. Without fighting an epic battle with with the sendmail configs, is there a simple way to make this work? Use lowercase usernames only. Make it a convention. Verify it. The obvious answer is probably, usernames should be lowercase! and for new users I'll enforce that policy. For existing users however, who may already have lots of case-sensitive usernames in various config files, etc this isn't a real option. That's true, but didn't this approach get you in trouble earlier? By just altering their usernames I'm afraid I'd break the whole damn universe. This is quite possible. As you mentioned correctly, usernames with uppercase letters may already appear in config files. You _could_ check for each user below his $HOME for any appearing in a file and replace this, but that could cause trouble if something is stored in a Registry-like binary file. Regarding /etc/passwd, the home directory _may_ be a different name than the username, so those _pathnames_ in files should not require a change. But files mentioning _usernames_ will probably cause problems. How can I enable mail for them? Maybe it's possible to use /etc/mail/aliases? -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Case sensitive usernames and sendmail - mystic voodoo
On Sun, May 26, 2013 at 6:17 PM, Polytropon free...@edvax.de wrote: On Sun, 26 May 2013 18:44:41 -0600, Modulok wrote: I know usernames are case-sensitive, I thought emails were too. If I remember e-mail basics correctly: No. They're not. For example, f...@example.com, f...@example.com and f...@example.com and all upper/lowercase variations are the same as f...@example.com. You remember incorrectly ;-) The local part of an address (before the @ sign) is case-sensitive (with the exception of postmas...@example.com) Everything to the right of the @ is indeed case insensitive, but everything to the left might be case sensitive, depending on local policy. This means you must preserve the case of everything to the left of the @ sign. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Case sensitive usernames and sendmail - mystic voodoo
On Sun, 26 May 2013 18:36:41 -0700, Michael Sierchio wrote: On Sun, May 26, 2013 at 6:17 PM, Polytropon free...@edvax.de wrote: On Sun, 26 May 2013 18:44:41 -0600, Modulok wrote: I know usernames are case-sensitive, I thought emails were too. If I remember e-mail basics correctly: No. They're not. For example, f...@example.com, f...@example.com and f...@example.com and all upper/lowercase variations are the same as f...@example.com. You remember incorrectly ;-) I checked again - and yes, it seems that my memory about the valid definition has changed to what is reality today, i. e. sendmail rewriting uppercase to lowercase prior to further processing. The local part of an address (before the @ sign) is case-sensitive (with the exception of postmas...@example.com) So it depends on how sendmail is configured that it does not matter today. Everything to the right of the @ is indeed case insensitive, but everything to the left might be case sensitive, depending on local policy. This means you must preserve the case of everything to the left of the @ sign. According to the link provided by Erich Dollansky, FreeBSD's default sendmail.cf setting of Mlocal, P=/usr/libexec/mail.local, F=lsDFMAw5 needs to be added the u option to the F= parameter to preserve the uppercase letters in the the left side (username) of the address. Maybe this additiion is required in other cf files containing Mlocal settings too? Of course it would be nice if there was a corresponding setting for the mc files which the cf files are usually generated from... -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Case sensitive usernames and sendmail - mystic voodoo
Everything to the right of the @ is indeed case insensitive, but everything to the left might be case sensitive, depending on local policy. This means you must preserve the case of everything to the left of the @ sign. According to the link provided by Erich Dollansky, FreeBSD's default sendmail.cf setting of Mlocal, P=/usr/libexec/mail.local, F=lsDFMAw5 needs to be added the u option to the F= parameter to preserve the uppercase letters in the the left side (username) of the address. Maybe this additiion is required in other cf files containing Mlocal settings too? Of course it would be nice if there was a corresponding setting for the mc files which the cf files are usually generated from... So, best practices aside, this would be a bug in the default config? (i.e. can I celebrate my bug-finding yet?) Cheers! -Modulok- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Case sensitive usernames and sendmail - mystic voodoo
On Sun, 26 May 2013 21:31:09 -0600, Modulok wrote: Everything to the right of the @ is indeed case insensitive, but everything to the left might be case sensitive, depending on local policy. This means you must preserve the case of everything to the left of the @ sign. According to the link provided by Erich Dollansky, FreeBSD's default sendmail.cf setting of Mlocal, P=/usr/libexec/mail.local, F=lsDFMAw5 needs to be added the u option to the F= parameter to preserve the uppercase letters in the the left side (username) of the address. Maybe this additiion is required in other cf files containing Mlocal settings too? Of course it would be nice if there was a corresponding setting for the mc files which the cf files are usually generated from... So, best practices aside, this would be a bug in the default config? No. A convention. :-) (i.e. can I celebrate my bug-finding yet?) Depends. If it's a _desired_ convention (because people regularly have problems with e-mail addresses and just don't care for upper and lower case), it's a good default setting. In _your_ case, it does not apply, because it introduces problems. So if you intend to make a local modification, that's no problem because you _can_ configure such things. This is the power that comes by the freedom of choice. You can celebrate this. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
