Comments 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

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By: wiki-test1-1 –SSD | test

wiki-test1-1 –SSD | test — Fri, 19 Jul 2013 22:29:34 +0000

[…] to boost performance on both desktop and server workloads. The bcache, dm-ssdcache, EnhanceIO and tier projects provide a similar concept for the Linux […]

By: snowman

snowman — Sun, 07 Apr 2013 18:28:52 +0000

Hi Maru,

I am really amazed at this project as my university project assigned me to do exactly the same thing. What I have done so far is only a user-space program that will migrate the file byte by byte or block by block to a block group specified by user (this is to simulate data migration between tiers). Also, my implementation is not a real-time tiering solution as the file system has to be unmounted when the program runs. In addition, as block bitmap, inode bitmap, group descriptor need to be updated, a lot of calculations are executed and it results an extremly slow speed when migrating a large file say tens of MBs. I didn’t expect such a poor performance before I completed the implementation. And this is also why I am super “shocked” when I see you implemented the feature by creating a kernel module.

Just out of curiosity, was this project done by yourself alone or there was a group of guys developing the solution? How long did you spend on it from an idea to the first version?

Your reply will be much appreciated.

Thank you.

Best regards,
Snowman Zhang

By: CS

CS — Thu, 10 Jan 2013 07:29:58 +0000

There is a person that was developing a tiered solution. There haven’t been any commits to the git project for ~5 months though. I’m interested if anyone else is working on something like this? Perhaps this is my chance to jump back into C.
https://bbs.archlinux.org/viewtopic.php?id=113529&p=2

By: Michael

Michael — Mon, 17 Dec 2012 22:06:45 +0000

Hi,
very interesting project, how is the actual status? Is there an active developer community, or a small group / single person? Is it beeing used in productive enviroments already? Same questions for lessfs

thanks,
Michael

By: rob

rob — Thu, 22 Nov 2012 18:19:02 +0000

Has anyone tried using tiered devices to back a drbd volume? Details of a known-good configuration would be great. “Do not go there” is also a good time saver if someone knows it’s not a go.

By: Calvin

Calvin — Fri, 27 Jul 2012 15:00:06 +0000

One follow up question – is it possible to add additional tiers to an existing tiered device?

By: Calvin

Calvin — Wed, 25 Jul 2012 23:27:21 +0000

Can a TIER device be expanded after creation (without data loss)? If one of the block devices below TIER is expanded (RAID capacity expansion), will TIER be able to use the new storage (tier_setup -d followed by tier_setup …) or is the TIER metadata specific to the initial block device sizes?

By: maru

maru — Tue, 26 Jun 2012 20:37:30 +0000

The storage layers that you ‘stripe’ together with tier should be protected with raid. Any device that fails will corrupt the whole tier device. So indeed, for production purposes one should use raid. When the SSD runs out of space the automatic tiering process will make sure that the blocks that are most frequently used are stored on SSD.
Blocks are moved by the optimization process. It uses statistics like how often the block is used and when it was used to decide if a block must be reallocated. Therefore the speed will be considerably higher then a simple RAID10.

By: dude

dude — Mon, 25 Jun 2012 05:29:31 +0000

“One advantage of tier when compared to SSD caching only is that the total capacity of the tiered device is the sum of all attached devices.”

But then if the one SSD fails, you lose all your data? Also, once the 160GB space of the SSD runs out, the rest of the 900GB space of the RAID 10 would be the same speed or lower than a simple RAID10, wouldn’t it?