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jens's questions

Martin Hope
jens
Asked: 2011-02-01 16:17:10 +0800 CST
  • 3

i want to install subversion. But I have already (manually) installed mysql. And it seems that aptitude will again try to intall mysql mysql-common{a}. How can I deselect the mysql installation when installing subversion? What commands/paramters do I need to use? I used -P but it seems it is not the correct option?

aptitude -P install  subversion

Paketlisten werden gelesen... Fertig
Abhängigkeitsbaum wird aufgebaut
Lese Status-Informationen ein... Fertig
Lese erweiterte Statusinformationen
Initialisiere Paketstatus... Fertig
Lese Task-Beschreibungen... Fertig
Die folgenden NEUEN Pakete werden zusätzlich installiert:
  libapr1{a} libaprutil1{a} libmysqlclient15off{a} libneon27-gnutls{a} libpq5{a} libserf-0-0{a} mysql-common{a}
  libsvn1{a}  subversion

Thank you very much!! Jens

debian aptitude
Martin Hope
jens
Asked: 2010-12-10 01:29:07 +0800 CST
  • 1

according to: http://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Tcp-handshake.svg/250px-Tcp-handshake.svg.png

1.) There is a 3 way TCP Establishment Handshake. Given I have a Ping-Time of 100 Millisecons, can I use the Ping-Time to calculate (in average) how long it will take to establish a TCP Connection?

2.) Given I have a Ping Time of 100 Millisecons, is it correct that it will require at least 150 Milliseconds? Or will it be 100 Milliseconds + one Microsecond (the microsecond is for sending the third ACK)? OR can the ACK even already contain data?

3.) What I do not understand is ( in the grafic above) when the Client know that his third ACK succeeded and he can now start sending regular data. I fully understand the SYN (1) then SYN ACK (2) and then ACK (3), but how does the Client know that the third ACK has been seent to the server and the client can start sending further information? Or is it as assumed above, that the third ACK can already contain data?

Thank you very much! Jens

networking tcp
Martin Hope
jens
Asked: 2010-12-06 22:02:42 +0800 CST
  • 32

I would be thankfull if someone who understands how LVM works, could tell me a rough estimate, how much slower using LVM (with a Software RAID1) will be.

(What I do not want to know how much slower LVM will be if the LVM Volume is currently in snapshot mode doing Copy on Write). I only need some rough estmiate how much LVM will slow down reads and writes in a normal operation scenario.

Any links are also very much appreciated I was not able to find any good performance benachmarks about this question.

performance lvm
Martin Hope
jens
Asked: 2010-11-26 17:43:17 +0800 CST
  • 0

it would be kind if someone who is an expert on this field state what I have to expect in regards to the latency accessing files for the given scenarios (comparing them):

A) Current Windows PC with an attachedn USB Harddisktrive

vs

B) Two current Windows PCs with the remote PC having an attached USB drive that will be accessed via WLAN (802.11g++) from the other PC.

=> The Question is how much slower will the access (in regards to latency) variant B) be? Will I notice the latency or will the latency be so small I will not notice it.

thanks!! jens

latency wlan