Re: [zfs-discuss] What is L2ARC write pattern?
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Jim Klimov One idea I have is that a laptop which only has a single HDD slot, often has SD/MMC cardreader slots. If populated with a card for L2ARC, can it be expected to boost the laptop's ZFS performance? You won't find that type of card with performance that's worth a damn. Worse yet, it will likely be extremely unreliable. In a SSD, all the performance and reliability come from intelligence in the controller, which emulates SATA HDD on one side, and manages Flash memory on the other side. Things like wear leveling, block mapping, garbage collection, etc, that's where all the performance comes from. You're not going to get it in a USB stick or a SD card. You're only going to get it in full size SSD's that consume power, and to some extent, the good stuff will cost more. (But of course, there's no way for the consumer to distinguish between paying for quality, and paying for marketing and margin, without trying it.) Even if you do try it, most likely you won't know the difference until a month later, having two identical systems with identical workload side-by-side. This is NOT to say the difference is insignificant; it's very significant, but without a point of reference, you don't have any comparison. All the published performance specs are fudged - but not lies - they represent optimal conditions, which are unrealistic. All the mfgrs are going to publish comparable specs, and none of them represent real life usage. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zfs send to older version
From: Richard Elling [mailto:richard.ell...@gmail.com] At some point, people will bitterly regret some zpool upgrade with no way back. uhm... and how is that different than anything else in the software world? No attempt at backward compatibility, and no downgrade path, not even by going back to an older snapshot before the upgrade. ZFS has a stellar record of backwards compatibility. The only break with backwards compatibility I can recall was a bug fix in the send stream somewhere around opensolaris b34. Perhaps you are confusing backwards compatibility with forwards compatibility? Semantics. New version isn't compatible with old version, or old version isn't compatible with new version. Either way, same end result. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zfs send to older version
Actually, I think there is a world of difference. Backwards compatibility is something we all need. We need to be able to access content created in previous versions of software in newer versions. You cannot expect an older version to be compatible with the new features in a later version. Those features did not exist when the software was written. You wouldn't expect to be able to open a document created in the latest version of MS Word (and saved in the latest format) in Word 95, would you? The only thing I think Oracle should have done differently is to allow either a downgrade or creating a send stream in a lower version (reformatting the data where necessary, and disabling features which weren't present). However, this would not be a simple addition, and it is probably not worth it for Oracle's intended customers. On 2012-10-23 14:01, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) wrote: From: Richard Elling [mailto:richard.ell...@gmail.com [1]] At some point, people will bitterly regret some zpool upgrade with no way back. uhm... and how is that different than anything else in the software world? No attempt at backward compatibility, and no downgrade path, not even by going back to an older snapshot before the upgrade. ZFS has a stellar record of backwards compatibility. The only break with backwards compatibility I can recall was a bug fix in the send stream somewhere around opensolaris b34. Perhaps you are confusing backwards compatibility with forwards compatibility? Semantics. New version isn't compatible with old version, or old version isn't compatible with new version. Either way, same end result. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org [2] http://mail.opensolaris.org/mailman/listinfo/zfs-discuss [3] Links: -- [1] mailto:richard.ell...@gmail.com [2] mailto:zfs-discuss@opensolaris.org [3] http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] Segfault running zfs create -o readonly=off tank/test on Solaris 11 Express 11/11
Hi, I have tried running zfs create -o readonly=off tank/test on two different Solaris 11 Express 11/11 (x86) machines resulting in segfaults. Can anybody verify this behavior? Or is this some idiosyncrasy of my configuration? Any help would be appreciated. Regards, Andreas ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Segfault running zfs create -o readonly=off tank/test on Solaris 11 Express 11/11
Hi Andreas, Which release is this... Can you provide the /etc/release info? It works fine for me on a S11 Express (b162) system: # zfs create -o readonly=off pond/amy # zfs get readonly pond/amy NAME PROPERTY VALUE SOURCE pond/amy readonly off local This is somewhat redundant syntax since readonly is off by default. Thanks, Cindy On 10/23/12 13:57, Andreas Erz wrote: Hi, I have tried running zfs create -o readonly=off tank/test on two different Solaris 11 Express 11/11 (x86) machines resulting in segfaults. Can anybody verify this behavior? Or is this some idiosyncrasy of my configuration? Any help would be appreciated. Regards, Andreas ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zfs send to older version
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Karl Wagner The only thing I think Oracle should have done differently is to allow either a downgrade or creating a send stream in a lower version (reformatting the data where necessary, and disabling features which weren't present). However, this would not be a simple addition, and it is probably not worth it for Oracle's intended customers. So you have a backup server in production, that has storage and does a zfs send to removable media, on periodic basis. (I know I do.) So you buy a new server, and it comes with a new version of zfs. Now you can't backup your new server. Or maybe you upgrade some other machine, and now you can't back *it* up. The ability to either downgrade a pool, or send a stream that's compatible with an older version seems pretty obvious, as a missing feature. I will comment on the irony, that right now, there's another thread on this list seeing a lot of attention, regarding how to receive a 'zfs send' data stream on non-ZFS systems. But there is no discussion about receiving on older zfs systems. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
