similar to: SSD Optimizations

Hi! With 3.2-rc4 (probably earlier), Ext4 seems to remember what areas it trimmed: merkaba:~> fstrim -v /boot /boot: 224657408 bytes were trimmed merkaba:~> fstrim -v /boot /boot: 0 bytes were trimmed But BTRFS does not: merkaba:~> fstrim -v / /: 4431613952 bytes were trimmed merkaba:~> fstrim -v / /: 4341846016 bytes were trimmed Is it planned to add this feature to BTRFS

I''ve got two recent examples of SSDs. Their pristine state from the manufacturer shows: Device Model: OCZ-VERTEX3 # hexdump -C /dev/sdd 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 1bf2976000 Device Model: OCZ VERTEX PLUS (OCZ VERTEX 2E) # hexdump -C /dev/sdd 00000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| *

On Mon, Feb 8, 2016 at 3:18 PM, <m.roth at 5-cent.us> wrote: > Chris Murphy wrote: >> DBAN is obsolete. NIST 800-88 for some time now says to use secure erase >> or enhanced security erase or crypto erase if supported. >> >> Other options do not erase data in remapped sectors. > > dban doesn't? What F/OSS does "secure erase"? And does it do

Hi, After reading through the btrfs documentation I''m curious to know if it''s possible to ever securely erase a file from a btrfs filesystem (or ZFS for that matter). On non-COW filesystems atop regular HDDs one can simply overwrite the file with zeros or random data using dd or some other tool and rest assured that the blocks which contained the sensitive information have

Here are patches to do offline deduplication for Btrfs. It works well for the cases it''s expected to, I''m looking for feedback on the ioctl interface and such, I''m well aware there are missing features for the userspace app (like being able to set a different blocksize). If this interface is acceptable I will flesh out the userspace app a little more, but I believe the

Hi all Is it possible to securely delete a file from a zfs dataset/zpool once it''s been snapshotted, meaning "delete (and perhaps overwrite) all copies of this file"? Best regards roy -- Roy Sigurd Karlsbakk (+47) 97542685 roy at karlsbakk.net http://blogg.karlsbakk.net/ -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et element?rt imperativ

For using SSDs: Are there any format/mount parameters that should be set for using btrfs on SSDs (other than the "ssd" mount option)? General questions: How long is the ''delay'' for the delayed alloc? Are file allocations aligned to 4kiB boundaries, or larger? What byte value is used to pad unused space? (Aside: For some, the erased state reads all 0x00, and for

Does BTRFS perform any journal and/or filesystem structure alignment (for benefit to SSD longevity and SSD, RAID array and large-sector device performance) at present? ext4''s Ted Tso will deliver 128KB alignment with the next release of e2fsprogs (ie 1.41.4) [1], so perhaps it''s a good idea for btrfsprogs also, if not already available? Daniel --- [1]

Hi, I was discussing the common practice of disk eradication used by many firms for security. I was thinking this may be a useful feature of ZFS to have an option to eradicate data as its removed, meaning after the last reference/snapshot is done and a block is freed, then write the eradication patterns back to the removed blocks. By any chance, has this been discussed or considered before?

I''ve been thinking about this for a while, from a perspective of how to make it work by allocating i-node numbers from a global pool, but yesterday I realized that offering the feature would be a bad idea because it violates the semantics of file systems. I will be happy to expand on that point if anyone disagrees with it. dln -- "It is merely a matter of persistence." --

How well suited is btrfs to low-end and high-end FLASH devices? Paraphrasing from a thread elsewhere: FLASH can be categorised into two classes, which have extremely different characteristics: (a) the low-end (USB, SDHC, CF, cheap ATA SSD); and (b) the high-end (SAS, PCIe, NAS, expensive ATA SSD). My own experience is that the low end (a) can have erase blocks as large as 4MBytes or more

Interesting flash technology overview and SSD review here: http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3403 and another review here: http://www.tomshardware.com/reviews/Intel-x25-m-SSD,2012.html Regards, -- Al Hopper Logical Approach Inc,Plano,TX al at logical-approach.com Voice: 972.379.2133 Timezone: US CDT OpenSolaris Governing Board (OGB) Member - Apr 2005

hi All, I''m new on the list. System: Distributor ID: Ubuntu Description: Ubuntu 13.04 Release: 13.04 Codename: raring Linux ctu 3.8.0-19-generic #30-Ubuntu SMP Wed May 1 16:35:23 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux The symptom is the same with Saucy 3.9 kernel. ii btrfs-tools 0.20~git20130524~650e656-0daily13~raring1 amd64 Checksumming Copy on

On Fri, September 8, 2017 9:48 am, hw wrote: > m.roth at 5-cent.us wrote: >> hw wrote: >>> Mark Haney wrote: >> <snip> >>>> BTRFS isn't going to impact I/O any more significantly than, say, XFS. >>> >>> But mdadm does, the impact is severe. I know there are ppl saying >>> otherwise, but I??ve seen the impact myself, and I

I just replaced my drives for Dovecot using Maildir format with a pair of Solid State Drives (SSD) in a raid 0 configuration. It's really really fast. Kind of expensive but it's like getting 20x the speed for 20x the price. I think the big gain is in the 0 seek time. Here's what I bought. Crucial RealSSD C300 CTFDDAC256MAG-1G1 2.5" 256GB SATA III MLC Internal Solid State

Hi folks, For people who might be interested, here is how btrfs performs with two partitions on a single SSD drive in a RAID-1 mirror. This is on a Dell E4200 with Core 2 Duo U9300 (1.2GHz), 2GB RAM and a Samsung SSD (128GB Thin uSATA SSD). Version 1.03c ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--

Hi, I don''t know if it''s already been discussed here, but while thinking about using the OCZ Vertex 2 Pro SSD (which according to spec page has supercaps built in) as a shared slog and L2ARC device it stroke me that this might not be a such a good idea. Because this SSD is MLC based, write cycles are an issue here, though I can''t find any number in their spec. Why do I

DBAN is obsolete. NIST 800-88 for some time now says to use secure erase or enhanced security erase or crypto erase if supported. Other options do not erase data in remapped sectors. Chris Murphy

Here is a short proposal for the hybrid storage cache idea with introduction/motivation and a bird''s eye view of an approach to implement a hybrid storage cache for btrfs. Please note that there is currently no available patches. We would like to get as much input before as possible before we start designing and implementing a solution. 1. Introduction The emerge of Solid State

On 09/08/2017 09:49 AM, hw wrote: > Mark Haney wrote: >> I hate top posting, but since you've got two items I want to comment >> on, I'll suck it up for now. > > I do, too, yet sometimes it?s reasonable.? I also hate it when the lines > are too long :) > I'm afraid you'll have to live with it a bit longer.? Sorry. >> Having SSDs alone will give you