search for: ssds

On 09/08/2017 01:31 PM, hw wrote: > Mark Haney wrote: > > I/O is not heavy in that sense, that?s why I said that?s not the > application. > There is I/O which, as tests have shown, benefits greatly from low > latency, which > is where the idea to use SSDs for the relevant data has arisen from.? > This I/O > only involves a small amount of data and is not sustained over long > periods of time. > What exactly the problem is with the application being slow with > spinning disks is > unknown because I don?t have the sources, and the...

...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 great performance regardless of >> filesystem. > > It depends, i. e. I can?t tell how these SSDs would behave if large > amounts of > data would be written and/or read to/from them over extended periods > of time because > I haven?t tested that.? That...

...Haney wrote: > On 09/08/2017 01:31 PM, hw wrote: >> Mark Haney wrote: >> >> I/O is not heavy in that sense, that?s why I said that?s not the application. >> There is I/O which, as tests have shown, benefits greatly from low latency, which >> is where the idea to use SSDs for the relevant data has arisen from. This I/O >> only involves a small amount of data and is not sustained over long periods of time. >> What exactly the problem is with the application being slow with spinning disks is >> unknown because I don?t have the sources, and the maker...

...ince 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 great performance regardless of filesystem. >> >> It depends, i. e. I can?t tell how these SSDs would behave if large amounts of >> data would be written and/or read to/from them over extended periods of time because >> I haven?t tested that. That isn?t...

I hate top posting, but since you've got two items I want to comment on, I'll suck it up for now. Having SSDs alone will give you great performance regardless of filesystem.? BTRFS isn't going to impact I/O any more significantly than, say, XFS.? It does have serious stability/data integrity issues that XFS doesn't have.? There's no reason not to use SSDs for storage of immediate data and m...

Hi, I was just wondering if there are specific steps to take to install CentOS on SSDs... By example, no swap partition? Format with a flash fs? Sysctl parameters? Thx, JD

Stephen John Smoogen wrote: > On 13 September 2017 at 09:25, hw <hw at gc-24.de> wrote: >> John R Pierce wrote: >>> >>> On 9/9/2017 9:47 AM, hw wrote: >>>> >>>> >>>> Isn?t it easier for SSDs to write small chunks of data at a time? >>>> The small chunk might fit into some free space more easily than >>>> a large one which needs to be spread out all over the place. >>> >>> >>> >>> the SSD collects data blocks being written and...

Hi Everyone, We are thinking of venturing into the world of hosting Windows DomUs on our Xen infrastructure. As Windows generally requires a lot more IOPS than Linux does, we are trying to do everything we can to improve performance. While using SSDs would solve the IOPS problem, SSDs suffer from limited write cycles. So, we have the idea of using Flashcache from Facebook to use a single SSD as a cache in write-through mode, along with spindle drives in RAID10. My questions to the community are: 1) What are the general views of using SSDs in...

Hi, When deploying ZFS in cluster environment it would be nice to be able to have some SSDs as local drives (not on SAN) and when pool switches over to the other node zfs would pick up the node''s local disk drives as L2ARC. To better clarify what I mean lets assume there is a 2-node cluster with 1sx 2540 disk array. Now lets put 4x SSDs in each node (as internal/local drives)...

John R Pierce wrote: > On 9/9/2017 9:47 AM, hw wrote: >> >> Isn?t it easier for SSDs to write small chunks of data at a time? >> The small chunk might fit into some free space more easily than >> a large one which needs to be spread out all over the place. > > > the SSD collects data blocks being written and when a full flash block worth of data is collected, o...

...ail spool on a filesystem and seems to hate being hammered with reads/writes. Personally, on all my mail spools, I use XFS or EXT4. OUr servers here handle 600million messages a month without trouble on those filesystems. > > Just my $0.02. Btrfs appears rather useful because the disks are SSDs, because it allows me to create subvolumes and because it handles SSDs nicely. Unfortunately, the SSDs are not suited for hardware RAID. The only alternative I know is xfs or ext4 on mdadm and no subvolumes, and md RAID has severe performance penalties which I?m not willing to afford. Part of the...

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 :) > Having SSDs alone will give you great performance regardless of filesystem. It depends, i. e. I can?t tell how these SSDs would behave if large amounts of data would be written and/or read to/from them over extended periods of time because I haven?t tested that. That isn?t the application, anyway. > BTRF...

...on disk to wipe level so it makes it >> opaque. The people who have tested this usually have to burn through >> an SSD set to get an idea about a particular 'run' of a model but it >> doesn't go over every version of the model of SATA SSD. > > > Hm, so much to SSDs ... I can only hope they will be replaced with > something better. > > > I have decided against putting anything onto these SSDs other than temporary > data, but even for that, I would need to make an md-RAID, which I don?t > want. > It may work or not, and "may work&quot...

...not need to be changed, but the old system was running on spinning discs and this is certainly not the best option for todays mail servers. With spinning discs, HW-RAID6 was the way to go to increase reliability and speed. Today, I get the feeling, that traditional RAID is not the best option for SSDs. I am reading that all RAID members in SSD-arrays age synchronously so that the risk of a massive failure of more than one disk is more likely than with HDDs. There are many other concerns like excessive write load compared to non-raid systems, etc. Is there any common sense what disk layout shoul...

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 u...

John R Pierce wrote: >> And one may want to adjust stripe size to be resembling SSDs >> internals, as default is for hard drives, right? > > as the SSD physical data blocks have no visible relation to logical block numbers or CHS, its not practical to do this. I'd use a fairly large stripe size, like 1MB, so more data can be sequentially written to the same device (...

I plan to upgrade an existing C7 computer which currently has one 256 GB SSD to use mdadmin software RAID1 after adding two 4 TB M2. SSDs, the rest of the system remaining the same. The system also has one additional internal and one external harddisk but these should not be touched. The system will continue to run C7. If I remember correctly, the existing SSD does not use a M2. slot so they should be available for the new 4GB SSDs...

hw wrote: > Mark Haney wrote: >> On 09/08/2017 09:49 AM, hw wrote: >>> Mark Haney wrote: <snip> > Probably with the very expensive SSDs suited for this ... <snip> >>> >>> That?s because I do not store data on a single disk, without >>> redundancy, and the SSDs I have are not suitable for hardware RAID. <snip> That's a biggie: are these SSDs consumer grade, or enterprise grade? It was commo...

On 13 September 2017 at 09:25, hw <hw at gc-24.de> wrote: > John R Pierce wrote: >> >> On 9/9/2017 9:47 AM, hw wrote: >>> >>> >>> Isn?t it easier for SSDs to write small chunks of data at a time? >>> The small chunk might fit into some free space more easily than >>> a large one which needs to be spread out all over the place. >> >> >> >> the SSD collects data blocks being written and when a full flash block...

Hi all, are there any plans that future versions of mkfs.btrfs will do an initial pre-discard for SSDs? (AFAIK mkfs.btrfs does not do this currently) For Ext4, mke2fs does this with the -E discard option. From the mke2fs manpage: -E discard Attempt to discard blocks at mkfs time (discarding blocks initially is useful on solid state devices and sparse / thin-provisioned storage). When the...