Comments for lessfs & btier

Comment on BTIER-1.3.3 and what it can do for you by Berto Obarrio

Berto Obarrio — Wed, 18 Mar 2015 13:40:57 +0000

Hello. One question .
I set the btier on CentOS , and I did run correctly , two levels of storage, files are copied first to the second , ok .
The problem : I restarted the machine, and was dismantled everything!
I had to redo insmod btier , reconfigure the disks, and tier 1 data were lost.
What I have to do to make when starting the machine is everything I had left ?
Thank You

Comment on btier-2.0.0 and btier-1.3.10 by Berto Obarrio

Berto Obarrio — Tue, 17 Mar 2015 16:55:38 +0000

Thanks!

Comment on btier-2.0.0 and btier-1.3.10 by maru

maru — Tue, 17 Mar 2015 16:54:03 +0000

The limit of 16 devices is a soft limit. It can be raised without problems.

Comment on btier-2.0.0 and btier-1.3.10 by Berto Obarrio

Berto Obarrio — Tue, 17 Mar 2015 15:33:08 +0000

Hello
I ‘m setting up a PACS DCM4CHEE on CentOS .
To manage different tiers of storage (online , intermediate, archived ) I fail to operate a hierarchical system .
I have been studying the btier , and I think it can be a great solution , the only doubt is the limitation of 16 discs .
In future iterations of btier such limitation shall be increased ? In the PACS many more discs may be required to store the studies.
Thank You.
Greetings .

Comment on Introducing TIER by How to: Home-brew automatic tiered storage solutions with Linux? (Memory -> SSD -> HDD -> remote storage) #it #development #fix | SevenNet

Sat, 10 Jan 2015 23:14:26 +0000

[…] http://www.lessfs.com/wordpress/?p=776 […]

Comment on BTIER-1.3.3 and what it can do for you by Riccardo

Riccardo — Thu, 25 Sep 2014 15:26:32 +0000

Hi Maru!
Just released a resource agent script for managing BTIER devices in Pacemaker Cluster Environment.
Hope someone find it useful

http://think-brick.blogspot.it/2014/09/btier-resource-agents-for-pacemaker.html

Comment on Lessfs-1.5.12 performance by Sonam

Sonam — Tue, 14 Jan 2014 05:28:43 +0000

Hello,

I have been trying to understand some of the configuration options for Lessfs and I want to make sure that we aren’t unnecessarily enabling/disabling options which may cause the performance to suffer.

I haven’t understood properly how exactly transactions work in this system, and why does it say that fsck is used to recover the file system after a crash if transactions are not enabled? Isn’t fsck a file system specific tool, how does it help recover the Lessfs database files? I apologie if this sounds like a naive question, I am very new to Lessfs.

Another question I had was how is the data actually stored in the file_io? I see that it is all stored in a single file. Are the unique blocks stored sequentially in this file? Or is it more like a hash table, where the block where the data is stored is determined by the hash? I actually did have a look at the data file and it looks like it is sequentially stored, but I’ve had some trouble understanding the mapping of offset in the database to the actual offset in this file.

Thank you very much. I apologize again for my naive questions, but I’ve spent a lot of time searching for answers, couldn’t really find too much about these details.

Regards,
Sonam

Comment on btier-0.9.9.9-3 has been released by matt

matt — Tue, 12 Nov 2013 05:41:15 +0000

unless you bought an Intel 3700 enterprise drive, you’ll want to configure your SSDs with no less than 25% spare area and 30% would be better. Most consumer drives only have 7% which is grossly inadequate in these kinds of workloads.

Comment on BTIER-1.0.0 stable has been released by maru

maru — Wed, 30 Oct 2013 10:46:51 +0000

Which btier version where you using when you had this problem?
What filesystem where you using? That e2fsck takes a long time on a 40+TiB volume is hardly a surprise.
Please reconsider if you even want a single volume to be that large or maybe switch to a journaled filesystem like xfs?

A problem that could potentially cause data corruption was solved in btier-1.1.0.

Comment on BTIER-1.0.0 stable has been released by Pulsed Media

Pulsed Media — Wed, 30 Oct 2013 10:04:49 +0000

A warning for everyone: I managed to get FS corrupted by a reboot.
It looks like one should always sync + detach btier before a reboot.

e2fsck gives warning was not cleanly unmounted, and we did try some manual block migrations as well – maybe that is part of the reason?

Not sure what causes this, but what we did was just a shutdown -r now, while all applications were still running (including iSCSI daemon) expecting things to be cleanly shutdown, unmounted etc.

Might be nothing particularly to do with btier – just the way we have things setup, so my point is that make sure you have all the necessary shutdown procedures in place.

Tho it still worries me a bit that FS got corrupted since servers are known to crash occasionally, and since this is 40+TiB array it takes a while to fsck.