From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mondschein.lichtvoll.de ([194.150.191.11]:54647 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbaFEQSJ convert rfc822-to-8bit (ORCPT ); Thu, 5 Jun 2014 12:18:09 -0400 From: Martin Steigerwald To: =?ISO-8859-1?Q?Sw=E2mi?= Petaramesh Cc: linux-btrfs@vger.kernel.org Subject: Re: Using BTRFS on SSD now ? Date: Thu, 05 Jun 2014 18:17:54 +0200 Message-ID: <3972210.UmLM5TcfW1@merkaba> In-Reply-To: <2215647.hErg5R77lo@zafu> References: <2215647.hErg5R77lo@zafu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am Donnerstag, 5. Juni 2014, 15:30:26 schrieb Swâmi Petaramesh: > Hi, > > I just received a new laptop with a Micron 256GB SSD, and I plan to install > Fedora 20 onto it. > > I'm considering either BTRFS or ext4 (over LUKS-encrypted LVM) for this > machine, but I'm afraid BTRFS might generate too much writes and shorten > the SSD lifespan... Or am I mistaken ? Relax. I don´t know why you come to the conclusion BTRFS would create more writes than other filesystems, but here are facts: BTRFS on Intel SSD 320, since about month or so as RAID 1 on Intel SSD 320 and Crucial m5 mSATA. BTRFS on Intel SSD 320 since I think a bit more than three years for now. SMART Attributes Data Structure revision number: 5 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 3 Spin_Up_Time 0x0020 100 100 000 Old_age Offline - 0 4 Start_Stop_Count 0x0030 100 100 000 Old_age Offline - 0 5 Reallocated_Sector_Ct 0x0032 100 100 000 Old_age Always - 0 9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 10289 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 2797 170 Reserve_Block_Count 0x0033 100 100 010 Pre-fail Always - 0 171 Program_Fail_Count 0x0032 100 100 000 Old_age Always - 0 172 Erase_Fail_Count 0x0032 100 100 000 Old_age Always - 169 183 Runtime_Bad_Block 0x0030 100 100 000 Old_age Offline - 1 184 End-to-End_Error 0x0032 100 100 090 Old_age Always - 0 187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0 192 Unsafe_Shutdown_Count 0x0032 100 100 000 Old_age Always - 241 199 UDMA_CRC_Error_Count 0x0030 100 100 000 Old_age Offline - 0 225 Host_Writes_32MiB 0x0032 100 100 000 Old_age Always - 449085 226 Workld_Media_Wear_Indic 0x0032 100 100 000 Old_age Always - 2204365 227 Workld_Host_Reads_Perc 0x0032 100 100 000 Old_age Always - 49 228 Workload_Minutes 0x0032 100 100 000 Old_age Always - 13212562 232 Available_Reservd_Space 0x0033 100 100 010 Pre-fail Always - 0 233 Media_Wearout_Indicator 0x0032 099 099 000 Old_age Always - 0 241 Host_Writes_32MiB 0x0032 100 100 000 Old_age Always - 449085 242 Host_Reads_32MiB 0x0032 100 100 000 Old_age Always - 1144183 Media Wearout Indicator was 100 initially, now is 99. Thus the SSDs considers itself to be basically new. Use search machine to find PDF of Intel about that value. And 449085 32 MiB Host Writes with KDE session, desktop search Nepomuk, now Baloo, Akonadi setups with insanely sized mailbox and what not. Thats: irb(main):027:0> 449085 * 32 / 1024.0 / 1024.0 => 13.704986572265625 13,7 TiB. This Intel SSD is specced for a useful life of 5 years with 20 GB host writes *each day*. Thats about 7 TiB per year, even if you use 1000 as base here. 3 years * 7 TiB = 21 TiB. So look at your SSD endurance specification and then just relax :) Ciao, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7