Posts made by drewlander

@scottalanmiller said:

@Dashrender said:

aww.. so SQL has DAGs now too, eh?

Yes, actually SQL is the only thing that has them. AD and Exchange are using SQL under the hood. When they need HA, it is their SQL that primarily needs it. DAG is a SQL thing (AFAIK) and applies equally to all SQL-based products.

Related to SQL but not iSCSI ( and not to hijack this thread ) I upgraded all my servers to MySQL 5.7 this weekend after finding out about the GTID and Channel features for multi-master replication. It works perfectly. This is a huge feature making multi-homed MySQL all-master all-active replication available in a community release. Someone should start a thread on this if there is not one already.

About the iSCSI, I think I recall I saw a similar error once and found out I was doing something wrong. More specifically I didnt have the allowed iscsi initiators set correctly.

thx
-d

@scottalanmiller said:

wn all of the

I lease with buyout from HP and use un-managed colo. An aged asset becomes a liability for my business continuity. However I dont think I would lease equipment from Rackspace fwiw. My aged hardware becomes dev hardware upon replacement.

thx
-d

@scottalanmiller said:

d only ever used semi-local. W

Wow! Toronto!? In HealthcareIT (When I worked for Eclipsys) I remember some problems we had because of conflicts between PHIPA and The Patriot Act. Id feel safer with my business in Toronto too, thinking about it.

150/25 Mediacom, DM, IA
$74 w basic cable.
At my local datacenter for my servers I pay $12/M 10/10 unlimited burst 95th%tile with a /28 subnet for BGP finished to my LAGG on Hurricane Electric and Cogent fiber.

thx
-d

@drewlander said:

I think I started the nethserver install once and got hung up on something or distracted and didnt go back to it. Ill be happy to install it and see how it compares.

Another thing that I was a little put off by with ClearOS is monitoring add-on was not free. Im not sure what they are offering but Nagios Core is freely available.

Some time I will need to put together a real technical analysis of these to break down the pros and cons, because they each have their own benefits and drawbacks.

@JaredBusch

So I tested ClearOS and its not bad. Compared to Zentyal the screens load much faster and config changes happen faster too. Must be something in the validations?? My biggest complaint is I cannot test everything without buying it. Zarafa. etc are not free even in the community edition. Id give it 3 out of 5 stars since I couldnt test all the functionality and because as you stated, this is a wrapper to manage all the packages and features they decide you should run in the distribution linux they choose.

Going back to my plan of testing LDAP\Samba4 and OX App on CentOS.

thx
-d

@scottalanmiller

I am installing it right now. Ill let you know.

@johnhooks
ClearOS looks pretty cool. I might tinker with this first.

@dafyre
Yes.

@scottalanmiller said:

Zentyal for a pure Linux environment would be really weird, though. Running Windows compatibility layers for systems that will talk to each other natively.

I dont think in many offices I can completely eradicate Windows desktops, but I am not against Samba4 and LDAP. I think it works quite well. That aside, I wanted to chime in on Zentyal since I recently tested it.

I finally fully evaluated Zentyal. Waste of my time. Its pretty much an Ubuntu install and web-based UI for people that probably shouldnt be touching a linux server. I can install LDAP and Samba4, and configure them without the help of their UI. The SOGo groupware is lacking because I feel like it should have something for Document Management. SOGo does not have a responsive UI for different viewports. Additionally the IMAP protocol will only support 50 connections, but I am guessing this is a Dovecot setting. Also you can only configure one domain per install which is totally lame.

My next test... LDAP\Samba4 and OX App, despite quite a few negative reviews I am willing to test it out.

If you have the dough to spend, Aerohive is really good stuff. Maybe I just like the platform better, but I see now that UBNT has upgraded UniFi, so I might need to thoroughly check it out before I commit to that statement. I just installed the new UniFi tonight because I saw this topic and wanted to check my config before commenting at all. If you want to do it on a budget, but not compromise the quality of the hardware then id go with the UBNT AP like @scottalanmiller suggested. Also I dont really bother with AC at this point because hardly any of my devices support it anyway, and I don't need those transfer speeds.

Keep in mind however ( not that this is a problem on my home network ) I think I recall reading some restrictions on those UBNT AP's. There was and may still be a hard limit of 127 devices per radio ( 127 @ 2.4 and 127 @ 5). In the forums people commented on a soft limit of 32 devices per AP, but I cannot attest to that having any accuracy. I don't know if you still need to configure wLAN groups for ZH (Zero Hand-off) to work, but it used to be that way for sure. Also there was a bug if you had the heartbeat checkbox enabled on the AP, MAC computers would randomly disconnect.

As far as switches go I really dont mind using inline adapters and barrel plugs with ac adapters. Id rather see one inline adapter fail than an entire POE switch, personally. This is really something you need to evaluate yourself.

I dont particularly like using Out-of-the-Box guest network configuration on UBNT equipment. My preference is to configure my own vLAN's and firewall rules. Last I knew you could have 4 SSID per AP, so I configure three. One for the managed network devices, one of personal devices and one for guests. Each SSID can be tied to a vLAN ID and you can introduce bandwidth policing at the SSID level. In my case, the managed network would be uncapped, the personal devices would have a minor cap, and guest networking would be "usable for general purposes". In the firewall I would isolate all three networks and block communication between them.

Anyway... that is my experience with these things. Hope at least one thing I mentioned helps you.

thx
-d

Thanks, Ill have a look. I wonder if they are features I would be concerned over.

Has anyone tried Zentyal CS with Samba to replace AD and MS Exchange? If so, did you migrate MS Exchange data? Did you encounter any issues? Was the user experience pretty seamless?

I am installing Zentyal right now to test this out, but I am curious if others have production experience on this topic.

@scottalanmiller Ah yes. I forgot that its a "hot data" caching system. I dont know if that is particularly useful for me.

Thats what I thought too. So if I wanted to make a major upgrade to these servers it would be better for me to use the SSD I already have for cachecade RAID1, then buy 4 2.5" 6Gb/s 15K 300Gb drives for a RAID5. That sound right?

@scottalanmiller said:

concerns remain the same, t

Any experience with LSI fastpath using SSD arrays as cache on the front end for a larger array of SAS spinning drives on the back end? LSI says its super fast, but that is their job to tell me that. I have been debating implementing one server like this to see how it goes.

@MattSpeller Based on what you just said I finally understand where @scottalanmiller is coming from. I concede that the writes are simultaneous to the disks therefore should not backlog the cache with exception in that queues and seeks will be based on your slowest disk.

@scottalanmiller said:

y zero write penalty

Sorry about the late response but I had some deadlines to meet and couldn't be distracted. In response:

Yes, I am concerned about disk endurance. That is why the disk exists at all.

I will agree that there is no write penalty if the cache does not get backlogged. The write cache is bypassing the write-through process where the disks tell the host that the write is complete. The cache still has to write the data to all the disks. Unless you can show me how an inequality of 3 < 2 is true, it is slower to write to three disks than two. I would surmise then with three disks the cache can get backlogged faster than with two disks because it has to deal with 33% more more writes before dumping that data from cache, which is entirely plausible in a high volume random write environment like OLTP systems.

Now since you got me thinking about this it has brought something to my attention that might be pretty important. The disk read fifo queue and disk write fifo queue are not necessarily in sync because the queues are not combined. This is true with or without a cache present, but negative implications could be much more prevailing with a cache present. When I commit a write transaction that gets stuck in cache and a read request is sent immediately after to retrieve that data, then it is theoretically possible the data I am expecting might not exist on the disk yet because its still in cache. Yikes!

I guess the point is, the configuration is entirely circumstantial. If I was serving web pages all day and not storing tons of micro data, then faster reads would be useful.

@Dashrender said:

e data to another server, retire server
BM2 - P2V to VM host
BM3 - P2V to VM host

Use BM2 hardware, in

im staying out of this one....

@scottalanmiller said:

@drewlander said:

On a side note, I pretty much only use RAID 1 mirror w 1 hot spare (3 disks total) these days in what I do.

Never use a hot spare with RAID 1 unless your controller really lacks basic functionality. Instead go to a triple mirrored RAID 1. This is far safer than RAID 1 with a hot spare because instead of needing to rebuild while lacking mirroring the data is always hot and ready AND you get a 50% read performance boost for the life of the array. So faster and safer, no downsides.

That's a pretty strong leading sentence. I want that spare inactive because the servers run SSD. Also I am not sure the gains on reads would be worth the hit on writes in an OLTP app that processes high volume micro transactions. We both know HDD's read faster than they write, and reads are not generally where people suffer with disk I/O issues (at least not in what I do). Id be happy to try it and compare random writes on a RAID1 3-way mirror cs RAID1 2 disk mirror, but I don't think I even need to do that to know 3x random writes takes longer than 2x random writes. Rebuild in degraded mode would be slower, but I would sooner prefer generally faster transactions with a day of slow rebuilding over a generally slower application from day to day.

-d